英语题Someone _______ in the classroom in the past.Nobody knows who he is

题目

英语题Someone _______ in the classroom in the past.Nobody knows who he is
1.选择（）Someone _______ in the classroom in the past.Nobody knows who he is.
A.heard to sing B.was heard sing C.heard sing D.was heard to sing
2.填空A dictionary is a very h______ tool to you when you learn language（我觉得用helpful,对吗.）

答案

D
be heard to do
Be heard doing
Helpful可以