GWD17-Q33

33. GWD17-Q33:

Doctors hope that one day the body’s master cells, called stem cells, can be directed to grow in organs or tissues appropriate for transplant, use them to test drugs and potentially toxic chemicals, and may study them to gain insight into basic human biology.

A.    transplant, use them to test drugs and potentially toxic chemicals, and may study them

B.    transplant, using them to test drugs and potentially toxic chemicals, and studied

C.    transplant, used to test drugs and potentially toxic chemicals, and studied

D.    a transplant, use them for testing drugs and potentially toxic chemicals, and for studying

E.     a transplant, used to test drugs and potentially toxic chemicals, and may study them

答案：C.这道题考三个动词的平行，这个没有什么问题，很显然ABDE是错的。但是C有一点我不是特别明白：C最后studied这个动词去掉了原文中的may这个情态动词修饰。一般来说，情态动词不可以省略，除非表示可能性时和原文中已经存在的表示可能性的词汇如probable，likely等重复要去掉，这里也没有这类表是可能性的词汇啊，是不是因为原文中主句谓语动词hope导致后面不用情态动词呢？请nn多多指教！！！！这个很puzzle的说。。。

恩，明白了哦，谢谢牛牛！

嗯

注意主语是cells，必须被动

恩，注意到了，3Q