问题补充：
According to a study carried out by an American university, when you eat has on your mood as you eat.
A. much of as an effect; what
B. much of as an effect; which
C. as much of an effect; what
D. as much of an effect; which
答案：
A. much of as an effect; what
B. much of as an effect; which
(答案→)C. as much of an effect; what
D. as much of an effect; which
解析：句意：据一家美国大学的研究，吃饭的时间与你吃的东西一样，对心情都会产生同样的影响。这里have an effect on对……有影响。as……as其中第一个as后不可以直接接名词； what引导的名词性从句,这里不是定语从句，因此不可以选用which。故选C。
