求问一道题：GWD第一套20题

fangfanggmat

20. In the middle-1970’s, since birdswere overcome by pollution, and routinely falling from the sky above Los Angelesfreeways, this prompted officials in California to devise a plan that reducedautomobile emmissions.  

A.     sincebirds were overcome by pollution, and routinely falling from the sky above LosAngeles freeways, this prompted officials in California to devise a plan thatreduced

B.     since birds/that had been overcome by pollution/ were routinelyfalling /from the sky above Los Angeles freeways/, it prompted officialsin California to devise a plan that would reduce

C.     birdshad been overcome by pollution and routinely fell from the sky above LosAngeles freeways, prompting officials in California to devise a plan thatreduced

D.     birds /overcome bypollution/ routinely fell from the sky above Los Angeles freeways, promptingofficials in California to devise a plan to reduce

E.      birdsovercome by pollution and routinely falling from the sky above Los Angelesfreeways, were prompting officials in California to devise a plan to reduce

答案选D. overcome怎么理解？

为什么不选B？

谢谢！

nancyyen

这个关键点就是看prompt的完成者是啥，文章原意也就是D选项是prompting前面的整个句子 prompting的， B的选项是it。你想it指代啥呢？ 这里it没有合理的指代对象。这种“，Ving”的考法经常出现。就是考察前后分句的逻辑关系。由的时候正确答案选Ving有伴随的关系，有的时候要选个从句来替换错误的“，Ving”因为前后句没有关系。你做到GWD后面就知道了