921.Anyway,that evening,_______ I'll tell you more about later,I ended up staying at Rachel's place.
A.when
B.where
C.what
D.which
922._________ is often the case,we have worked out the production plan.
A.Which
B.When
C.What
D.As
921.答案是D;which引导非限制性定语从句，代指that evening,作about的宾语。
922.答案是D;as在句中指代we have worked out the production plan这件事;which引导非限制性定语从句指代整个句子时，只能放在主句之后，不可在句首。
