the back door of our classroom is hardA.to be opened B.to open C.being open D.to open it

问题描述:

the back door of our classroom is hard
A.to be opened B.to open C.being open D.to open it

B
be hard to do sth
很难打开

b
很难打开
be + 形容词 + 动词 这里不需要用被动