I can't see the words on the blackboard.Why,your eyes need to be _英语解答

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?

人气：231 ℃　时间：2019-10-08 20:50:40

解答

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.