Very few people are to be seen in the streets after 8 pm.为什么用are _英语解答

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?

人气：326 ℃　时间：2020-05-18 18:57:15

解答

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.