【be supposed to do / be sth本应该是...】
指某事是预期的或被要求做的(或本应该是怎样）,如:
You're supposed to buy a ticket,but not many people do.
你们本来是需要买票的,但并没多少人买.
I thought we were supposed to be paid today.
我以为今天我们就会收到款的.
The engine doesn't sound like it's supposed to.
这引擎的声音听起来不像平时它发出的声音.
You were supposed to be here an hour ago!
一小时前你就该在这儿的!
How was I supposed to know you were waiting for me?
我怎么会知道你在等我?
'Yes and no.' 'What is that supposed to mean?'
‘是~也不是.’（表示不满）