It was ____ the old worker came that we ____ the experiment.

What _____ if you don’t take a taxi to the party

You look nice in your new dress! When did you buy it—Don’t you know I ______it for several days.

The local people like to dance _______ the rhythm of a kind of large drum; that is something typical _______ their culture

Tom，you aresmoking again- It’s none of your business．