求助prep34，关于or在肯定句中用法

ursula_1

34。

 Hundreds of species of fish generate and discharge electric currents, in bursts or as steady electric fields around their bodies, using their power either to find and attack prey, to defend themselves, or also for communicating and navigating.

 

(A) either to find and attack prey, to defend themselves, or also for communicating and navigating

(B) either for finding and attacking prey, defend themselves, or for communication and navigation

(C) to find and attack prey, for defense, or communication and navigation

(D) for finding and attacking prey, to defend themselves, or also for communication and navigation

(E) to find and attack prey, to defend themselves, or to communicate and navigate

对于这道题我有个小小疑问，正确答案是E,我想请教大牛，

to do, to do and to do,一直以为or只是用在否定句中，现在看来，or也可以用在肯定句中吗？

能否再多给个例子，谢谢！

Jiangchuandi

or表示选择,可以用在肯定句中

ursula_1

但这里，用and就不可以吗？

vivian0331

以下是引用Jiangchuandi在2009-5-2 23:36:00的发言：
or表示选择,可以用在肯定句中

同意。可不可以这样理解，ursula_1 MM:

to find and attack prey或to defend themselves或to communicate and navigate 三种不同的功能，表示三个方向，任何一个都可以，并不是三者都取，他们之间的关系是“或”的关系而不是“与”的关系。

另，即使是or也是并列结构。

再另，既然题目四个选项都是or，在考场上做这道题时就没那功夫想那么多了……

ursula_1

嗯，好的，谢谢lsmm！应该是这样理解的