当公交车上全是人时. When a bus is full of people. 为什么这里用is不用are

当公交车上全是人时. When a bus is full of people. 为什么这里用is不用are The bus is full of people.There are no______(seat) the room is full of people.这里be full of 为什么要用is很多人不是应该用are吗? 一道初三英语补全对话A：The train station is full of people during Natio 哪一个是你 Which one is you?这里为什么不用are而用is? The world is full of very rich people who are as miserable a look!the bus is coming -----but it is full of people we can It is a waste of time doing this这里为什么用doing而不用do?为什么? there is a lot of traffic and pollution.为什么用is不用are Don't worry.Look!Here comes the bus.为什么这里用comes而不用is coming look there are lots of people（）the bus.A is waiting forB wai why is a room full of married people empty?