孩子们应该在上午8点45分前到校。

The children ___are ___supposed ___to ___be at school by 8.45 a.m.

你在床上做什么？你应该在睡觉的！

What are you doing out of bed? You ___are ___supposed ___to ___be asleep!

这应该是一个惊喜。

It ___was ___supposed ___to ___be a surprise.