there were not any in sight

问题描述:

there were not any in sight
There were not any in sight.They ____(新概念2P145)
A could not be seen B were not seen
选哪个?为什么?

选A
第一个的意思是视野内一个也没有,联系上下文也就是说我找不到他们,这里用they做主语,被动语态,也就是 他们不能被发现.