题目内容：

know Jack spends at least as much time reading as he__________.
A does writing
B is writing
C writes

优质解答

A
as后面是省略句,这句话分析的时候把句子还原,可以去掉不影响句子主干的部分,就可以看出
I know Jack spends time reading as he spends writing
然后为了避免重复 将spends 用does代替.