It's supposed to... 应该……用法透视该句表示“按道理讲应该……”，可用来表达猜想或命令(相当于should)等含义。

　　支持范例

　　1. He is supposed to arrive on the 5 o'clock train.

　　他应该乘五点的火车到达。

　　2. Summer is supposed to come during May.

　　夏天应该在五月来临。

　　3. It was supposed to be ready last week.

　　这件事上星期就该做好的。会话记忆

　　A: Hey, how was the show?

　　嗨，那场演出怎么样?

　　B: Not great. It's a kind of boring.

　　不怎么样。有点乏味。

　　A: Really? I heard it was supposed to be great.

　　是吗?我听说它应该很棒的。

　　B: Yes, me too. But I'm disappointed.

　　我也这么听说。但我很失望。