Question

The children _______ basketball in the playground sometimes. A.were seen playB.were seen to play

C.have seen to play D.have seen play

Answer 1

选　B，这道题运用的是过去时的被动语态，一般过去时的被动语态的结构是：
was /were +过去分词，同时被动语态中原来的see sb. do sth.要变成 see sb. to do sth.
不知这样讲，你清楚了没？

Answer 2

c