The man downstairs found ___ very difficult to get to sleep .A.them B.that C.what D.it

题目

The man downstairs found ___ very difficult to get to sleep .A.them B.that C.what D.it

答案

D.
it是形式宾语真正的宾语是后面的to get to sleep.可以转换成宾语从句如下：
the man downstairs found that it was difficult to get to sleep.