GWD的一道题，急求大牛指导~~~~

非欧2011

By the same techniques used for genetically enhancing plants, making them disease- or pest-resistant, researchers have been able to increase the amount of protein in potatoes, sweet potatoes, and tobacco.



A. By the same techniques used for genetically enhancing plants, making them

B. With the same techniques to genetically enhance plants, so that they are

C. Employing the same techniques used to genetically enhance plants so that they are

D. Employing the same techniques to genetically enhance plants, which makes them

E. Employing the same techniques for genetically enhancing plants that make them

 C项中的employ 和used 不会造成语义的重复吗？？？？？

Tshirtzhe

这题排除法，最后选了c
A和B modifier 不能形容 researcher 排除
D which 指代不明
E them 指代不明，可以是 plants or techniques
C 我感觉 employ 是modify researcher , used to 是 modify techniques

非欧2011

顶~求指导