I can't see the words on the blackboard.Why,your eyes need to be examined.为什么不能直接说need to examined,而要加be?这里be的用法谁能帮我解释一下?

问题描述:

I can't see the words on the blackboard.
Why,your eyes need to be examined.
为什么不能直接说need to examined,而要加be?这里be的用法谁能帮我解释一下?

这里是被动语态
一定要用Be Done 的结构
如果按Need 的特殊用法也可以说
Why,your eyes need to be examining.
(Need to be done=need doing)

be+动词过去分词,被动语态,表示被...
...你的眼睛需要(被)检查一下.