____ to a high temperature, water will change into vapor [ ]

Whatever you have found，you should give it back to whomever it ________

In the past, the workers were made __________ 12 hours a day.

Why not ask Tony to go to the cinema together with us —He _____Shanghai on business , and ____back in two weeks .

John, look at the time. _____ you play the piano at such a late hour—Oh, sorry.