The following questions present a sentence, part of which or all of which is underlined. Beneath the sentence, you will find five ways of phrasing the underlined part. The first of these repeats the original; the other four are different. If you think the original is best, choose the first answer; otherwise choose one of the others.
These questions test correctness and effectiveness of expression. In choosing your answer, follow the requirements of standard written English; that is, pay attention to grammar, choice of words, and sentence construction. Choose the answer that produces the most effective sentence; this answer should be clear and exact, without awkwardness, ambiguity, redundancy, or grammatical error.
The stock market collapse of 1929 had far-reaching consequences for the national economy, causing a nationwide collapse in home values, putting millions out of work, and by erasing the investment savings of one-fifth of the population.（）
A. and by erasing
B. and erasing
C. and having erased
D. and erased
E. by erasing
参考答案：B
解析：
To maintain a parallel structure with "causing" and "putting," the verb in the final clause should be "erasing" without "by;" the presence of "by" in the phrase does not make sense with the rest of the sentence. B is the clearest and most idiomatic choice.