it must have rained last night,__the ground is wet this morning.A for B since C because D as这个应该选A吗?为什么不是C或者D呢?

问题描述:

it must have rained last night,__the ground is wet this morning.
A for B since C because D as
这个应该选A吗?为什么不是C或者D呢?

for 后面表示的原因不是直接原因.