英语选择题，解释一下

来源：百度知道 编辑：UC知道 时间：2024/06/09 02:22:53
When I try to understand ________ that prevents so many Americans from being as happy as one might expect, it seems to me that there are two causes.
A. why it is B. what it is C. why it does D. what it does

B
因为后面有 two causes...反过来看，就是 what are the causes, 所以是B
不可能说 why are the causes 或 what do the causes..

选B
（ ）that prevents so many Americans from being as happy
空格处缺名词形式，所以应填what it is

选B
这是一个强调句，it is ……that……类型的强调句，由于这不是一个问句，所以用what it is 而不是what is it

选B
首先what引导it is 作understand的宾语从句 然后再做it is ……that……类型强调句中it is 后面的成分，也即 prevents so many Americans。。。的主语。

B
what it is that prevents so many Americans from being as happy as one might expect做understand的宾语从句。这个宾语从句是个强调句型即it is。。。that。。。，即句子本身应是 it is what prevents so many Americans from being as happy as one might expect，因为what是疑问词，所以放在宾语从句的前面