Very few people are to be seen in the streets after 8 pm.

问题描述:

Very few people are to be seen in the streets after 8 pm.
为什么用are to be seen?
这是什么知识点?

八点之后,街上很少有人.
be to do句型,表示未来将要,注定发生的事;
see在此处应该用被动形式 be seen,
人们被看到.