题目内容：

英语试题2
Glaciers begin to form------more snow falls during the winter than melts and evaporates in the summer.
A is when
B when there are
C when
D when does
为什么选C 不是B

优质解答

when引导时间状语从句.
若选B,即构词句子 there are more snow falls during the winter than melts and evaporates in the summer. 此句存在语法错误,因为后面出现了谓语动词falls和evaporates. 故不能用there be 型.
故选C.