In the mid-1970's, since birds were overcome by pollution, and routinely falling from the sky above...

题目信息

In the mid-1970's, since birds were overcome by pollution, and routinely falling from the sky above Los Angeles freeways, this prompted officials in California to devise a plan that reduced automobile emissions.

A:since birds were overcome by pollution, and routinely falling from the sky above Los Angeles freeways, this prompted officials in California to devise a plan that reduced

B:since birds that had been overcome by pollution were routinely falling from the sky above Los Angeles freeways, it prompted officials in California to devise a plan that would reduce

C:birds had been overcome by pollution and routinely fell from the sky above Los Angeles freeways, prompting officials in California to devise a plan that reduced

D:birds overcome by pollution routinely fell from the sky above Los Angeles freeways, prompting officials in California to devise a plan to reduce

E:birds overcome by pollution and routinely falling from the sky above Los Angeles freeways were prompting officials in California to devise a plan to reduce

参考答案及共享解析

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正确答案： D:birds overcome by pollution routinely fell from the sky above Los Angeles freeways, prompting officials in California to devise a plan to reduce

(A)were overcome和and后面的routinely falling不对称，而且因为falling前有and，所以也不可能falling是修饰前面整个一句话或者修饰birds/pollution；this在句中单独出现，是指代错误，不能指代前面整个句子，无指代对象；

(B)我拿到的选项内容是same as A，so no comments；

(C)had been overcome过去完成时，整个题干没有过去完成时的标志，考虑错；

(D)正确；

(E)were prompting这个时态过去进行时，一般无明显标志或者时间说明考虑错；

笔记