Our hometown is quite different from _______before.
A.that is was
B.what it was
C.which it was
D.when it was
答案B
解析what引导的从句作介词的宾语,并在从句中兼作表语,而that,which,when则不能。

Our hometown is quite different from _______before.
A.that is was
B.what it was
C.which it was
D.when it was
答案B
解析what引导的从句作介词的宾语,并在从句中兼作表语,而that,which,when则不能。