GMAT：OfficalGuide语法部分(一).

　　Explanatory Material:

　　0Sentence Correction

　　The following discussion is intended to familiarize you with the most ficient and fective approaches to sentence correction questions. The particular questions in this chapter are generally representative of the kinds of questions you will encounter in the GMAT. Remember that it is the problem-solving strategy that is important, not the specific details of a particular question.

　　1. The Wallerstein study indicates that even after a decade young men and women still experience some of the fects of a divorce occurring when a child.

　　(A) occurring when a child

　　(B) occurring when children

　　(C) that occurred when a child

　　(D)that occurred when they were children

　　(E) that has occurred as each was a child

　　D is best. The phrasing a divorce that occurred when they were children correctly uses the relative clause that occurred to modify a divorce and includes a pronoun and verb (they were) that rer unambiguously to their antecedent, men and women. Choice A incorrectly introduces the when... phrase with occurring, thus illogically making divorce the grammatical rerent of when a child; furthermore, the singular child does not agree with the plural men and women. B replaces child with children but otherwise fails to correct A&aposs errors of structure and logic, and C corrects only the error created by occurring. Choice E includes an incorrect verb tense (has occurred) and wrongly replaces when with as. Also, each was does not properly rer to men and women.

　　2. Since 1981, when the farm depression began, the number of acres overseen by professional farm-management companies have grown from 48 million to nearly 59 million, an area that is about Colorado&aposs size.

　　(A) have grown from 48 million to nearly 59 million, an area that is about Colorado&aposs size

　　(B) have grown from 48 million to nearly 59 million, about the size of Colorado

　　(C) has grown from 48 million to nearly 59 million, an area about the size of Colorado

　　(D) has grown from 48 million up to nearly 59 million, an area about the size of Colorado&aposs

　　(E) has grown from 48 million up to nearly 59 million, about Colorado&aposs size

　　In choice C, the best answer, an area about the size of Colorado clearly describes a rough equivalence between the area of Colorado and the area overseen by the companies. In A and B, the plural verb have does not agree with the singular subject number. Choice A is also wordy, since that is can be deleted without loss of clarity. The absence of an area in B and E impairs clarity: the phrase beginning with about must modify a noun such as area that is logically equivalent to the number of acres given. In D and E up to is unidiomatic; the correct expres­sion is from x to y. In D, the size of Colorado&aposs is unidiomatic, since of Colorado forms a complete possessive.

　　3. Some bat caves, like honeybee hives, have residents that take on different duties such as dending the entrance, acting as sentinels and to sound a warning at the approach of danger, and scouting outside the cave for new food and roosting sites.

　　(A) acting as sentinels and to sound

　　(B) acting as sentinels and sounding

　　(C) to act as sentinels and sound

　　(D) to act as sentinels and to sound

　　(E) to act as a sentinel sounding

　　Because the verb phrases used to describe the bats&apos duties are governed by the phrase different duties such as, they should each be expressed in the present participial (or "-ing") form to parallel dending and scouting. Choices A, C, D, and E all violate parallelism by employing infinitives (to...) in place of participial phrases. In E the singular sentinel is not consistent with residents, and the omission of and distorts the meaning of the original. Only B, the best answer, preserves the sense of the original, uses the correct idiom, and observes the parallel­ism required among and within the three main verb phrases.

　　4. The only way for growers to salvage frozen citrus is to process them quickly into juice concentrate bore they rot when warmer weather returns.

　　(A) to process them quickly into juice concentrate bore they rot when warmer weather returns

　　(B) if they are quickly processed into juice concen­trate bore warmer weather returns to rot them

　　(C) for them to be processed quickly into juice concentrate bore the fruit rots when warmer weather returns

　　(D) if the fruit is quickly processed into juice concen­trate bore they rot when warmer weather returns

　　(E) to have it quickly processed into juice concentrate bore warmer weather returns and rots the fruit

　　For parallelism, the linking verb is should link two infinitives: The only way to salvage ... is to process. Choice A begins with an infinitive, but the plural pronouns them and they do not agree with the singular noun citrus. Choices B, C, and D do not begin with an infinitive, and all present pronoun errors: the plural pronouns cannot grammatically rer to citrus or fruit, nor can they rer to farmers without absurdity. The best choice, E, has parallel infinitives and uses fruit to rer unambiguously to citrus. E also expresses the cause-and-fect relationship between the return of warmer weather and the rotting of the fruit; A, C, and D merely describe these events as contemporaneous.