问题

If you try to understand _____ that prevents so many Americans from being as happy as one might expect, it seems that there are two causes. [ ]

A: what it does
B: why it is
C: why it does
D: what it is

正确答案是：

同类题型

I think he is _______ young _______ go to school.

All the students in my class ____ those heroes and decided to learn from them.

He wrote his novel when he was .

As is proved, real effective exchange rate appreciation will help improve our country’s industrial structure in the long run, though it ______ some short-term pressure on employment.

______ we can’t remove our troubles in life for ever, we can leave them behind when we are on vacation[ ]