问题

When I try to understand ________ that prevents so many children from being happy, there seem to be three causes.

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

正确答案是：

同类题型

Seeing their son playing computer games all day, the parents don’t know ______ it.

How do you like sit-ups(仰卧起坐)—Very much. I’m good at doing sit-ups. But it won’t be liked by .

Some experts have said that ________ children believe they can succeed, they will never become totally confident of themselves

What’s this in English—-_____________.

Good afternoon! Millie. Welcome to our library. Which book would you like—I’d like books about animals. Can I ______ some, Mrs. Yang