求问一道题 Prep2008 234题

Chloe-Chen

The coyote is one of several recent ecological success stories: along with the white-tailed deer, the moose, and other species that are enlarging their natural domains, they have established themselves as supreme adapters in an era when the capability to adjust to the environmental changes wrought by human beings has created a whole new class of dominant large mammals.

A they have established themselves as supreme adapters in an era when the capability

B they have established themselves as being supreme adapters in an era when being able

C it has established itself as a supreme adapter in an era when to be able

D it has established itself as being a supreme adapter in an era when its ability

E it has established itself as a supreme adapter in an era when the ability

问题在于C和E, C中 when to be able......和 E的 when the ability to.....为什么C不行呢  不定式不是也能作主语吗 麻烦大家来解救一下我。。。。

Chloe-Chen

有木有大神呀 求指导！

咖啡印象

不定式作主语，通常用来表示一件未完成的事或目的，是一个具体的、特定的行为。

比如：To complete the program needs much effort. 完成这项计划需要很大的努力（这项计划未完成）

而直接用名词形式，通常表示一件抽象的，概括性的事情或者经验。

Chloe-Chen

咖啡印象 发表于 2017-5-19 09:57
不定式作主语，通常用来表示一件未完成的事或目的，是一个具体的、特定的行为。

比如：To complete the pr ...

那意思是 这道题这里的to be able to在这里是没有缺失成分之类的语法错误 只是说使用不当吗