A-A+
When I try to understand ______ that prevents
问题详情
When I try to understand ______ that prevents so many Americans from being happy as one might expect, it seems to me that there are two causes.
A．what it does
B．what it is
C．why it does
D．why it is
参考答案
正确答案：B
解析：名词性从句。what引导的名词性从句作动词understand的宾语，宾语从句是一个it is...that...的强调句型，that之后的prevents缺少主语，故正确答案为B。
