We left the door unlocked.___could have come in.

问题描述:

We left the door unlocked.___could have come in.
(1) Anybody
(2) Somebody
(3) Everybody
(4) Nobody

2
门没有锁,推断有人进去过.所以是对过去情况的一种推测,是虚拟语气的一种.
你可以看下虚拟语气的相关资料就会明白了