TOEFL EXERCISE ON MODALS

1.    On the average, a healthy heart _____ to pump five tablespoons of blood with every beat.

a.       Must        b. ought        c. can         d. should

2.    It is generally believed(a) that Thomas Jefferson was the one who has researched and wrote(b) the Declaration of Independence during the months prior to its signing(c)  in July 1776(d)

3.    In general, by the second year of production, the price of a new piece of technology ______significantly.

a.       Will decreased    b. has decreased    c. will have decreased   d. will has decreased

4.    Although some higher structures(a) have been build(b) in New York City, none characterizes(c) the skyline better than(d) the Empire State Building.

5.    Research in genetics and DNA having(a) had a profound(b) influence on(c) the direction of treatment for a large number(d) of diseases

6.    Bones(a) composed(b) chiefly(c) of calcium, phosphorous, and a fibrous substance known as(d) collagen.

7.    A cure for juvenile diabetes ______ until more funds are allocated to basic research.

a.       Won’t develop     b. aren’t developing   c. don’t develop   d. won’t be developed

8.    During(a) the past decade, twenty million college graduates spended(b) more than(c) fifty billion dollars in ten-year(d) student loans.

9.    Civil engineers had better _____ steel supports in concrete structures built on unstable geophysical sites.

a.       Include     b. including   c. inclusion   d. included

10. There is no(a) time limit to the diversity to be finding(b) in the cultures(c) of people(d) throughout the world.

11. The cones of pine trees______ two or three years to reach maturity.

a.       To take     b. taking   c may take   d. takes

12. The government requires that a census taken(a) every ten years(b) so that accurate statistics(c) may be compiled(d)

13. It is important that cancer is(a) diagnosed(b) and treated as early as possible(c) in order to assure(d) a successful cure.

14. Although the scientific community had hoped that the field transplantation ______, the shortage of organ donors has curtailed research.

a.       Progress  b. had progressed   c. would progress   d. progressing

15. Before railroad lines(a) were extended(b) from Missouri to New Mexico, millions of dollars in trade was used to be carried(c) over the Santa Fe Trail by wheeled wagons(d).

16. Based on a decline in vehicular deaths during the past decade, seat belts, air bags, baby seats(a), and other safety features in newer(b) automobiles must be save(c) lives(d).

17. The gold(a) used In jewellery is not strong enough(b) unless it(c) be(d) alloyed.

18. Even without strong wings, the ostrich has survived because it _____ at high speeds to escape predators.

a.       To run     b. can run     c. running     d.run

19. General damage that been caused(a) by aphids or pollution(b) is sometimes(c) known as(d) blight.

20. Fred Astaire is said to had been the most popular dancer of his time, but he was also a talented actor, singer, and choreographer.

ANSWER KEY

1.    (B) ought to is used before to to express obligation. A healthy heart should pump would also be correct. Choices a, b, and d are modals that are used before verb words, not before to.

2.    (B) Wrote should be written because the auxiliary had requires a participle. Wrote is a past form. Written is a participle.

3.    (C) will have is used before the participle decreased to predict the future, by the second year of production. The modals in choices (A) and (D) require a verb word, not past and present forms of the verb. Choice (B) expresses a past, not a future, point of view.

4.    (B) A passive sentence is used to focus on the structures rather than on the builders. In a
passive sentence, a form of be is followed by a participle. Build should be built.

5.    (A) Every sentence must have a main verb. Having should be has.

6.    (B) Every sentence must have a main verb. Composed should be are composed.

7.    (D) Won't means will not. Won 't is used before be followed by the participle developed in a passive to express the importance of the cure. "Scientists won't develop a cure until more funds are allocated" would also be correct to express the importance of the scientists. Choices (B) and (C) do not express future. Choice (A) is not a passive.

8.    (B) The past form of the verb to spend is spent. Spended should be spent.

9.    (A) Had better requires a verb word. Choice (B) is an -ing form, not a verb word. Choice (C) is a noun. Choice (D) is a past verb.

10. (B) The participle is used after a form of BE in a passive sentence. Finding should be found after to be.

11. (C) Every English sentence must have a subject and a main verb. Choice (A) is an infinitive, not a main verb. Choice (B) is an -ing form. Choice (D) is a main verb, but it does not agree with the plural subject cones.

12. (A) A verb word must be used in a clause after the verb to require. Taken should be be taken.

13. (A) A verb word must be used in a clause after an impersonal expression such as it important that. Is should be be.

14. (C) Had hoped that introduces a clause with a subject and would followed by a verb word. Choice (A) is a verb word without would. Choice (B) is had followed by a participle. Choice (D) is an -ing form.

15. (C) Used to requires a verb word to express a custom in the past. Was used to be carried should be used to be carried.

16. (C) Must followed by be and an -ing form expresses a logical conclusion about an event that is happening now. Save should be saving.

17. (D) Unless introduces a clause with a subject and a main verb. Be should be is to maintain the point of view established by is in the previous clause, jewelry is.

18. (B) The modal can followed by a verb word expresses ability. The infinitive in Choice (A) the –ing form in Choice (C), and the verb word in Choice (D) do not express ability.

19. (A) A form of HAVE followed by a participle expresses a duration of time. The participle been is a form of BE used with the participle caused in a passive before the agent by the aphids or pollution. Been caused should be has been caused.

20. (B) A form of HAVE followed by a participle expresses a duration of time. The infinitive is to have. Had been should be have been after to.