I've forgotten everything____I saw and heard about in the town.

I've forgotten everything____I saw and heard about in the town.
A、that
B、which
C、what
D、when
【正确答案】：A
【题目解析】：考察定语从句，由于先行词为everything 不定代词，因此只能使用that ，在从句中做saw 和hear about的宾语。