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Section 1. GUIDELINES FOR READING ACADEMIC TEXTS

REVISION: MAIN TOPIC AND SUBTOPICS, TEXT ORGANIZATION, MAKING INFERENCES, EXPLICATION OF SPECIFIC INFORMATION

MAIN IDEA, SUBHEADINGS, KEY WORDS, VOCABULARY IN CONTEXT, SPECIFIC WORDS

Instruction: This is a revision unit in which you should combine all skills you have employed in the preceding eight units. You will have to start with identifying the main idea, the main topic, or the main purpose of the text. Then follows the task of: matching headings with paragraphs or sections, and identifying which sections relate to certain topics. Basing on circumstantial evidence, inferences and vocabulary-in context you will have to look into specific information given in the text.

Text: Earth’s Threatened Ozone Layer

A) One of the most disturbing aspects of the changes in Earth is the rate at which chemical pollutants produced by human activity are destroying the protective layer of ozone in Earth’s upper atmosphere. Ozone is a molecule that consists of three oxygen atoms. An oxygen gas molecule consists of two oxygen atoms. Reactions between oxygen and ultraviolet radiation from the sun create a layer of ozone throughout Earth’s stratosphere (upper atmosphere).

Although ground-level ozone is considered a harmful pollutant, the ozone layer in the stratosphere is beneficial. The layer normally absorbs 95 to 99.9 per cent of the ultraviolet radiation from the sun, protecting life on Earth from this biologically damaging form of energy.

Ultraviolet radiation causes skin cancer — including malignant melanoma, a form of the disease that can be fatal — and other health problems. Ultraviolet radiation increases the risk of cataracts, which cloud the lens of the eye and can cause blindness. It may also weaken the human body’s disease-fighting immune system. Scientists fear that the continued depletion of the ozone layer in the upper atmosphere will thus cause widespread health problems.

Ultraviolet radiation threatens other forms of life as well. It may interfere with plant photosynthesis, causing ecological damage and reducing agricultural production. Ultraviolet radiation may also damage marine life by killing one-celled plants called phytoplankton, which form the base of the ocean’s food chain. Krill (small, shrimplike animals) feed on phytoplankton. Krill, in turn, are a major source of food for many sea animals, including penguins, seals, and whales.

B) In 1974, scientists first proposed the idea that manufactured chemicals could threaten the ozone layer. A group of widely used gases called chlorofluorocarbons (CFC’s) posed the greatest chemical threat.

These gases have a variety of uses. Electronic equipment manufacturers use CFC’s to clean metal, and CFC’s are commonly used as refrigerants and to make foam insulation. Aerosol sprays may also contain the compounds. The United States banned the use of CFC’s in aerosol sprays in 1978, but many other countries still permit this use. Finally, halon gases, which are used in fire extinguishers, are also CFC’s.

Each year, the world us

es approximately 750,000 metric tons (827,000 short tons) of CFC’s. Much of those gases are sealed in refrigerators and air conditioners, where they do not threaten the environment. However, some CFC’s escape from leaking, poorly serviced, or discarded appliances. Industrial processes such as electronics and insulation manufacturing also release CFC’s into the atmosphere.

Once in the upper atmosphere, CFC’s react with ozone to destroy it. First, ultraviolet light breaks down CFC molecules. One of the products of this breakdown is the element chlorine. As a single chlorine atom or when combined with one oxygen atom as chlorine monoxide, this element breaks down ozone molecules. Scientists estimate that one chlorine atom can destroy as many as 100,000 ozone molecules.

C) The frigid temperatures and atmospheric conditions above Antarctica favor the destruction of ozone. Scientists believe that tiny ice crystals of nitric acid in Antarctica’s upper atmosphere are directly involved. These crystals may help begin the chemical changes that result in the destruction of ozone.

In 1985, British scientists confirmed that chemical reactions had begun to damage the ozone layer above Antarctica. They reported results from ozone measurements taken with instruments on the ground, in airplanes, and put aloft in scientific balloons during the previous 27 years. Their measurements showed a 40 per cent reduction in ozone concentrations over Antarctica from the mid1970’s to 1984. This thinning occurred during September and October — springtime in the Southern Hemisphere. Media reports dubbed the annual thinning a «hole» in the ozone layer.

Many groups of scientists quickly began monitoring the Antarctic ozone layer. In 1986, U.S. National Aeronautics and Space Administration (NASA) scientists confirmed the British findings and found that the hole in the ozone layer was nearly as large as the entire continent of Antarctica. In 1987, scientists reported that the hole was wider and deeper than in 1986, and that it lasted longer. In 2001, scientists reported that, during 1990’s, Antarctic ozone levels had dropped to their lowest recorded level.

D) The danger of ozone destruction is not limited to Antarctica, however. In April 2007, the U.S. Environmental Protection Agency (EPA) reported that atmospheric ozone concentrations above the United States decreased by 5 to 6 per cent during the 2000’s, three times faster than during the 1970’s. The EPA report fueled concerns that cases of skin cancer and deaths due to melanoma would rise dramatically in the United States in future decades.

In October 1991, United Nations scientists reported that ozone losses above the United States and other temperate areas of Earth between the tropics and the poles were taking place during summertime. This alarmed many experts, who feared that the summer decrease in the protective ozone layer could cause even more cases of skin cancer.

In February 2002, NASA scientists announced that levels of chlorine monoxide resulting from the breakdown of CFC’s were at record levels above the Northern Hemisphere near the Arctic and that these conditions could cause an ozone hole to develop over much of Europe, Canada, Russia, and northern portions of the United States by the year 2010.

For an ozone hole to form, proper weather conditions must also exist. In April 2004, NASA scientists reported that ozone-layer depletion above the Arctic was not as extensive as expected because of unusually warm weather. The weather helped break up a pattern of strong, cold winds called the circumpolar vortex. These winds help trap chlorine monoxide and speed ozone destruction. But scientists said that if the circumpolar vortex lasts longer than usual in future years, a large ozone hole can be expected to develop above the Arctic.

E) Scientists and politicians worldwide are working to slow the destruction of the ozone layer. In September 1987, 24 nations, including the United States, signed an agreement in Montreal, Canada, to limit the production of CFC’s. The agreement, called the Montreal Protocol, froze CFC production at 1986 levels, beginning in 1989. The 24 nations also agreed to reduce CFC production by 50 per cent by 1999.

Since the Montreal Protocol, however, most nations have agreed that an even quicker phase-out of CFC’s is needed. In June 1990, the world’s industrial nations agreed to halt all production of CFC’s by the year 2000. Some countries adopted an even more rapid phase-out schedule. Most European nations planned to stop producing CFC’s by the end of 1995, and the United States announced in February 1992 that it would also stop making the chemicals by the end of 1995.

But CFC’s remain in the atmosphere for at least 75 years before natural processes break them down and the chlorine washes out of the atmosphere as hydrochloric acid in rain. So even if all CFC production stopped immediately, the threat of ozone depletion would continue for more than a century. And the CFC’s needed for industry are not easily replaced. There are, however, substitutes for most uses, including refrigeration. The challenge for scientists and chemical engineers is to find substitutes that will be as effective as CFC’s — and that will not have some other group of harmful effects.

F) While some researchers concentrate on the car and improving its systems and materials, others focus on the fuel that feeds the car. On at least one occasion, car improvements and fuel refinements went hand in hand. When catalytic converters were developed, the petroleum industry had to make gasoline leadfree. Leaded gasoline produces emissions containing lead, which coats the metals in the converter, rendering them ineffective. Because lead has been linked to cancer and can cause nervous-system damage in children, lead-free gasoline was an important development against automobile pollution.

Researchers continue to search for ways to make better gasoline. Refining crude oil to produce gasoline involves heating the oil and drawing off various types of hydrocarbons as they evaporate. Some hydrocarbons, such as butane,are lightweight molecules that evaporate easily. Others, such as benzene, are heavier, have a tendency to form deposits and particulates, and may be cancercausing.

Petroleum companies can create gasolines that pollute less by using more hydrocarbons from the middle of the weight spectrum — those that are neither very light nor very heavy. Refiners can also break down or «crack» some of the heavier hydrocarbons to yield lighter compounds. Some gasoline additives, such as methyl tertiary butyl ether — commonly known as MTBE — include oxygen atoms in their structure. This helps promote more complete fuel combustion.

G) Researchers are also investigating fuels other than gasoline. Methanol (an alcohol made from ingredients derived from such sources as natural gas, wood, coal, sewage, or garbage) emits smaller quantities of pollutants normally associated with gasoline combustion. But it has less potential energy than does gasoline, and it is more difficult to ignite. Methanol also can corrode (eat away) many of the metals, sealants, and resins used in automobiles. Finally, methanol produces formaldehyde, a toxic compound that can irritate the eyes, nose, and throat, and which is thought to cause cancer. On the positive side, methanol burns more completely than does gasoline, and when mixed with 15 per cent gasoline to form a fuel called M-85, it achieves satisfactory starting performance. A «flexible fuel» engine can run on either gasoline or methanol or a combination of both. Special sensors determine the type of fuel in use and relay this information to the central computer system.

Natural gas is another abundant fuel that experts consider an alternative to gasoline. It is composed mainly of methane gas and is cheaper and much cleaner than gasoline. This fuel’s major drawback is that, unlike gasoline and methanol, it is not available as a liquid at normal air temperatures and pressures. Natural gas must be carried in a pressurized tank, or, as a liquid, in an insulated tank — unfamiliar additions to a car’s design that consumers may reject. Refueling with natural gas could take up to several hours.

Some scientists are interested in hydrogen as the fuel of the future. Hydrogen burns much more cleanly than do other fuels and is easy to produce. But complex technical problems must be solved before it can be widely used in cars.

Electric vehicles are quiet and virtually emission-free. However, the batteries from which they draw energy usually contain toxic chemicals, which become pollutants when the batteries are disposed of. Today’s electric cars cannot go as far or as fast as gasoline-driven vehicles because the battery does not offer the same amount of energy as does gasoline combustion. Furthermore, the battery must be recharged regularly, and the energy to do this comes from power plants that are also a source of pollution. Nevertheless, electric vehicles are the likely choice for meeting zero-emission laws that have been established in some areas, such as California.

The ongoing search for ways to make cars cleaner poses a demanding challenge to engineers, as well as chemists, materials scientists, and technicians. The widespread research reflects our newly heightened concerns for the environment along with our old desire to maintain the freedom of movement that the automobile has brought to the developed world.

Task: Answer the following questions:

  • What is the main topic of the passage?

A) Human activity is destroying the protective layer of ozone in Earth’s upper atmosphere.

B) Manufactured chemicals could threaten the ozone layer.

C) Scientists are working to slow the destruction of the ozone layer.

D) Better gasoline will improve the protective layer of ozone.

  • What is the author’s attitude toward the Montreal Protocol freezing CFC production?
  • Where in the four sentences does the author discuss harmful pollutants interfering with the protective layer of ozone in Earth’s upper atmosphere?

A) Although ground-level ozone is considered a harmful pollutant, the ozone layer in the stratosphere is beneficial.

B) Ultraviolet radiation threatens other forms of life as well.

C) The frigid temperatures and atmospheric conditions above Antarctica favor the destruction of ozone.

D) A group of widely used gases called chlorofluorocarbons (CFC’s) posed the greatest chemical threat.

Read the passage: Methanol emits smaller quantities of pollutants normally associated with gasoline combustion. But it has less potential energy than does gasoline, and it is more difficult to ignite. Methanol also can corrode (eat away) many of the metals, sealants, and resins used in automobiles. Finally, methanol produces formaldehyde, a toxic compound that can irritate the eyes, nose, and throat, and which is thought to cause cancer. On the positive side, methanol burns more completely than does gasoline, and when mixed with 15 per cent gasoline to form a fuel called M-85, it achieves satisfactory starting performance.

  • Which of the following can be inferred about methanol?

A) Methanol causes cancer.

B) Gasoline doesn’t produce toxic compounds.

C) Methanol is easier to ignite..

D) The best fuel is a composition of methanol and gasoline.

Task: Match the following 7 headings with letters A, B, C, D, E, F, G.

Antarctica’s ozone destruction A

Ozone losses above the US B

Ultraviolet radiation C

Ozone-destroying chemicals D

Alternatives to gasoline E

Gasoline refinement F

Protecting the ozone layer G

Your task is to choose the correct one from the list of headings provided. You should skim a paragraph or section before choosing the correct answer from the list. Remember that it is more efficient to skim the long piece of text first and get the idea of the whole text. Then you can look through the alternative headings very quickly.

Step 1 Survey the text

The list of headings will give you some clues to help you quickly understand what each part of the text is about.

Step 2 Skim read each paragraph

Every paragraph deals with a specific aspect of a topic. The first sentence of a paragraph may tell you what the rest of the paragraph is about. Therefore while trying to identify the main idea of a paragraph, you should read the first sentence and skim the rest of the paragraph.

Task: Scanning the text for key words.

This title Earth’s Threatened Ozone Layer can help you understand that key words must concern any kinds of polluting activities or be connected with destruction of ozone layer. E.g., in paragraph A it is possible to point out the following key words: chemical pollutants, ozone layer, ultraviolet radiation, to protect, to destroy, to damage, health problems, food chain.

Follow the three-step strategy to make finding key words easier.

Step 1 Make sure you know what you are looking for.

Step 2 Scan each paragraph for 5-10 key words. Do not read every word.

Step 3 Select 5-10 key words for the whole text.

Task: Use your general background knowledge, knowledge of the general context, your knowledge of parts of speech and root words.

Your knowledge and experience about what is logical or illogical can help you guess the meaning of some words. Let us take, for instance, the first passage of paragraph A and the last passage of paragraph B. These two passages are logically connected in that they explain how the reaction of ozone creation and destruction is going on:

«One of the most disturbing aspects of the changes in Earth is the rate at which chemical pollutants produced by human activity are destroying the protective layer of ozone in Earth’s upper atmosphere. Ozone is a molecule that consists of three oxygen atoms. An oxygen gas molecule consists of two oxygen atoms. Reactions between oxygen and ultraviolet radiation from the sun create a layer of ozone throughout Earth’s stratosphere (upper atmosphere).»

«Once in the upper atmosphere, CFC’s react with ozone to destroy it. First, ultraviolet light breaks down CFC molecules. One of the products of this breakdown is the element chlorine. As a single chlorine atom or when combined with one oxygen atom as chlorine monoxide, this element breaks down ozone molecules. Scientists estimate that one chlorine atom can destroy as many as 100,000 ozone molecules.»

As you may see, there are words with opposing meanings in these passages: to create, to produce, products, on the one hand, and to destroy, destroying and to break down, breakdown, on the other hand.

Basing on this opposition you can build a logical chain: Reactions between oxygen and ultraviolet radiation create ozone — Reactions between CFC and ultraviolet radiation produce chlorine — Reactions between ozone and chlorine destroy ozone.

This logical chain presents the main idea of the whole text.

Your knowledge of the root word can also help you make up word nests for your vocabulary, e.g.: to destroy, destroying, destruction, destructive. Make up word nests for the following words: to pollute, to produce, to protect.

Task:

  • Basing on paragraph C explain how media called a «hole» in the ozone layer.
  • Basing on paragraph D explain what concerns were fueled by ozone losses above the US.
  • Basing on paragraph E explain what the threat of ozone depletion means.
  • Basing on paragraph F explain the difference between light band heavy hydrocarbons.
  • Basing on paragraph G explain the negative and positive sids of methanol.

Task: Collect specific information by pointing out groups of synonyms, semantic and thematic groups. Keep it in mind that vocabulary in context includes both single words (usually nouns, verbs, adjectives, and adverbs). and twoor three-word phrases.

It is claimed in paragraph A that ultraviolet radiation causes skin cancer. Continue this list and find other names of health problems.

Find a synonym for the word to stop in paragraph E.

Point out names of alternative fuels mentioned in paragraph G.

Explain a contrast in the following sentences from paragraph G: Hydrogen burns much more cleanly than do other fuels and is easy to produce. But complex technical problems must be solved before it can be widely used in cars.

What is the referent word for the verb do?

Section 2. GUIDELINES FOR GRAMMAR TEST

Errors with prepositions

Errors with prepositions are among the most difficult errors to catch. Preposition use in English is very complex. For every rule, there seems to be an exception. There are many errors involving prepositions, and they are more difficult to spot.

Prepositions are used in the following ways:

In adverbial phrases that show time, place, and other relationships: in the morning, on Central Avenue, to the park, by a student

After certain nouns: a cause of , a reason for, a solution to.

After certain adjectives and participles: different from, aware of, disappointed in. After certain verbs: combine with, rely on, refer to.

In phrasal prepositions (twoor three-word prepositions):according to, together with, instead of.

In certain set expressions: by far, in general, on occasion, at last.

There are two main types of preposition errors that you may see your test:

Errors in preposition choice

Such errors take place when the wrong preposition is used according to the context of the sentence.

Some of the rules for choosing the correct prepositions are given below, but you will never be able to memorize all the rules for preposition use in English. The more you practice, though, the more you will develop a «feel» for determining which preposition is correct in any given situation.

There are two particular situations involving preposition choice:

Errors with from . . . to and between . . . and

Both these expressions are used to give the starting time and ending time. They can also be used to show relationships of place and various other relationships. E.g.:

  • He lived in Seattle from 1992 to 1997.
  • He lived in Seattle between 1992 and 1997.
  • Route 66 ran from Chicago to Los Angeles.
  • Route 66 ran between Chicago and Los Angeles.

It will be a mistake to say: The highway runs between Simferopol to the port of Yalta, a distance of 60 miles.

The correct pattern is from…to.

Errors usually involve an incorrect pairing of those words, or the incorrect use of other prepositions. E.g.::

between A to B from X and Y

between A with B since X to Y

Errors with since, for, and in

Since is used before a point in time with the present perfect tense—but never with the past tense. For is used before a period of time with the present perfect and other tenses. In is used before certain moments in time (years, centuries, decades) with the past tense and other tenses—but never with the present perfect tense. E.g.:

He’s lived here since 1995.

He’s lived here for two years.

He moved here in 1995.

Errors involve the use of one of these prepositions for another. E.g.: He’s lived here in 1995.

He’s lived here since two years. He moved here since 1995.

Corn was the population’s main item of food since at least 2000 years. Before a period of time (2,000 years) the preposition for should be used.

Errors with on

The pitch of a tuning fork depends of the size and shape of its arms. The correct preposition after the verb depend is on, not of.

Incorrect inclusion or omission of prepositions

A preposition is often used when one is not needed, or not used when one is needed.

According many critics, Mark Twain’s novel Huckleberry Finn is his greatest work and is

one of the greatest American novels ever written.

The preposition to has been omitted from the phrase according to.

Some of the most of spectacular caves are found in the Crimean mountains. The preposition of should not be used in this phrase. (When most means «majority,» it can be used in the phrase most of the. «Most of the people agree...,» for example. However, in this sentence, most is part of the superlative form of the adjective spectacular, and so cannot be used with of.

Exercise: Identify correct and incorrect preposition choice.

Directions: Underline the prepositions that correctly complete the sentences below.

Wage rates depend (in/on) part (from/on) the general prosperity (of/for) the economy.

(For/To) an injection to be effective (on/against) tetanus, it must be administered (by/within) 72 hours (of/for) the injury.

The invention (of/for) the hand-cranked freezer opened the door (for/to) commercial ice-cream production, and (for/since) then, the ice-cream industry has grown (in/into) a four-billion-dollar-a-year industry.

(At/On) the time (of/in) the Revolutionary War, the North American colonies were merely a long string (with/of) settlements (along/among) the Atlantic Coast (between/from) Maine and Georgia.

The probability (of/for) two people (in/on) a group (of/for) ten people having birthdays (in/on) the same day is about one (in/of) twenty.

Showboats were floating theaters that tied up (at/to) towns (in/on) the Ohio and Mississippi Rivers to bring entertainment and culture (to/at) the people (on/in) the frontier.

Scrimshaw, the practice (of/for) carving ornate designs (in/on) ivory, was first practiced (by/of) sailors working (by/with) sail needles while (in/on) long sea voyages.

Bird Island, (off/of) the coast (off/of) the Crimea, is famous (for/to) its flocks (of/with) wild geese.

(In/On) order (for/to) an object to be visible, light must travel (from/for) that object (at/to) a person’s eves.

Mini-test

Identify and correct errors involving prepositions

Chemical pollutants produced by human activity are destroying the protective layer of ozone between Earth’s surface to upper atmosphere.

Ozone concentrations above the United States decreased by 5 to 6 per cent

from 1990 and 2000.

Ultraviolet radiation causes a range of health problems — between skin cancer with blindness.

United Nations scientists reported ozone losses since 1991 to 2001 above temperate areas of Earth between the tropics to the poles.

NASA scientists announce that levels of chlorine monoxide resulting from the breakdown of CFC’s have been at record levels since 10 years.

24 nations, including the United States, signed an agreement since September 1987 planning to limit the production of CFC’s.

They promised to limit the production of CFC’s since at least 20 years. This agreement has been validated in 1991.

Depending of their measurements a 40 per cent reduction in ozone concentrations over Antarctica took place between the mid-1970’s to 1984.

On March 1974, scientists first proposed about the idea that manufactured chemicals could threaten to the ozone layer.

Choose the right preposition

A group (in/of/for) widely used gases called chlorofluorocarbons (CFC’s) posed the greatest chemical threat

Researchers continue to search (on/for/in) ways to make better gasoline.

While some researchers concentrate (at/in/on/to) the car and improving its systems and materials, others focus (at/in/on/to) the fuel that feeds the car.

Methanol also can corrode (in/on/no preposition/at/for) many of the metals, sealants, and resins used (in/on/ no preposition/at/for) automobiles.

(In/On) order (for/to) electric engines to be used in automobiles the must be made more effective.

Because lead has been linked (in/on/with/to) cancer and can cause (in/on/no preposition/at/for) nervous-system damage in children, lead-free gasoline was an important development (for/against/about/in) automobile pollution.

(For/To) the organic fuel to be effective (on/against/with/for) pollution, it must be a combination (on/of/in/with) gasoline and methanol.

(At/On) the time (of/in) Earth’s dangerous pollution, search for ways to make cars cleaner poses a demanding challenge (for/with/on/to) engineers, as well as chemists.

The concern (of/for) the scientists working (in/on) fuel industry to find a new fuel (of/for/with) automobiles is heightened (by/ along with/at) our old desire to maintain the freedom of movement that the automobile has brought (at/for/to) the developed world.


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