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TOEFL Preparation: Lesson 4 - Petroleum Alternatives

Target Words

  1. constraint

  2. contamination

  3. deplete

  4. dispose of

  5. elementally

  6. emission

  7. extinction

  8. reservoir

  9. shrink

  10. stable

Definitions and Samples

1. constraint n. Something that restricts thought or action

The constraints of military life kept Eileen from seeing Private Morris more than once a month.

Parts of speech constrain v

2. contamination n. Being made less clean by a germ or hazardous substance

The contamination in the river came from the factory located just upstream.

Parts of speech contaminate v, contaminant n

3. deplete v. To greatly decrease the supply of a resource or material

The prolonged war depleted the country’s national treasury.

Parts of speech depletion n

4. dispose of v. To throw away; to get rid of; to kill

She disposed of her unwanted possessions before moving.

The tyrant cruelly disposed of all his enemies.

Usage tips Dispose of should be learned as a unit. In this meaning, dispose does not occur without of.

Parts of speech disposal n, disposable adj

5. elementally adv. In terms of elements; basically

Elementally, coal and diamonds are the same.

Parts of speech element n, elemental adj

6. emission n. Sending out from a small space into the general environment; a substance discharged into the air

The Environmental Protection Agency regulates the emission of pollutants into the air.

Usage tips Emission is usually followed by an of phrase.

Parts of speech emit v

7. extinction n. Complete disappearance; the end of existence

Human beings have caused the extinction of many other species.

Usage tips Extinction implies an absolute end; an extinct thing cannot be brought back into existence.

Parts of speech extinct adj

8. reservoir n. A place where a liquid is collected and stored

Cult members threatened to poison the town’s water reservoir.

Parts of speech reserve v

9. shrink v. To become reduced in size, amount, or value

If you dry your clothing on the “high heat” setting, they may shrink.

Parts of speech shrinkage n, shrinkable adj

10. stable adj. Firm and dependable; showing little change

He fell because the ladder wasn’t stable.

Parts of speech stability n, stably adv


Find the word that is closest in meaning to the opposite of each word in the left-hand column.

Write the letter in the blank.

1. stable (a) keep

2. contamination (b) expand

3. extinct (c) unsteady

4. dispose of (d) existing

5. shrink (e) purity


Circle the word that best completes each sentence.

1. The (constraints/contamination) of being in prison made her hate society even more.

2. A recognition that the Earth is round was one of the (elemental/shrunken) advances in thought during the time period.

3. Mother Teresa, who helped the poorest of the poor, had a great (disposal/reservoir) of love within her spirit.

4. Automobiles are responsible for some (emissions/extinction) of greenhouse gases.

5. By the end of the storm, the hikers had (depleted/reserved) even their emergency stores.

TOEFL Success

Read the passage to review the vocabulary you have learned. Answer the question that follows.

Human consumption of fossil fuels is expected to fully deplete the Earth’s crude oil reserves by the year 2060. As underground reservoirs of oil continue to shrink, we have no choice but to find alternatives.

One promising source, with much cleaner emissions, is called bio-diesel. Bio-diesel is often made from soybean oil, although it can be made from any vegetable oil that is not elementally different from soy. Bio-diesel can even be made from used cooking oils that homes or restaurants would otherwise dispose of. Bio-diesel can be used without constraint in any vehicle that runs on diesel—no modifications are needed.

Presently, diesel engines can take up to 20 percent soy in their soy-diesel blend. As the need for bio-diesel increases and the technology improves, we may soon witness the extinction of the fossil-fueled vehicle. This is good news for the planet, as bio-diesel is a more stable source of energy than petroleum, and it reduces contamination of our air and water.

An introductory sentence for a brief summary of the passage is provided below. Complete the summary by selecting the three answer choices that express the most important ideas in the passage. In each blank, write the letter of one of your choices.

Bio-diesel is a promising alternative to fossil fuels.

  1. _________________

  2. _________________

  3. _________________

a. Humans have shown little self-restraint in their consumption of fossil fuels.

b. Underground reservoirs of oil will soon be depleted.

c. Bio-diesel burns cleaner than fossil fuels.

d. Bio-diesel comes from a more stable source than petroleum.

e. Restaurants can save disposal fees on used cooking oil.

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