The question he asked is hard ____ .

问题描述:

The question he asked is hard ____ .
The question he asked is hard ____ .
为什么是to answer 而不是 to be answer
是我打错了,应该是to be answered ,那为什么有的题目不定式后也可以用被动呢?

因为一句话里只能有一个动词