prep-1sc-45

45.   (26929-!-item-!-188;#058&003015)

The application of a new method for analyzing the chemistry of tooth enamel allows scientists to examine molars of prehuman ancestors and determining that their diets were more varied than had been supposed.

(A) The application of a new method for analyzing the chemistry of tooth enamel allows scientists to examine molars of prehuman ancestors and determining

(B) Through the application of a new method for analyzing the chemistry of tooth enamel, the molars of prehuman ancestors were examined by scientists who determined

(C) When they applied a new method for analyzing the chemistry of tooth enamel, scientists examined molars of prehuman ancestors, determining

(D) Applying a new method for analyzing the chemistry of tooth enamel, the molars of prehuman ancestors have been examined by scientists, who determined

(E) Applying a new method for analyzing the chemistry of tooth enamel, scientists have examined molars of prehuman ancestors and determined

E是最好的答案，但是我对时态有疑问，前面是现在完成时，后面是过去式和过去完成时，是不是跨度太大了？

本句时间结构是合理的

现在完成时表示过去的动作对现在的影响,跟过去时用在一起时间框架是一致的

后面是一个比较,是过去的情况跟过去的过去进行比较,因此用了过去完成时