Look at the clock! It's time ______ work.

----- Oh, my goodness! My laptop must have got stolen． ----- But where _____ a thief have entered the house with all the doors and windows still locked?

 To be on the safe side, we should fill up the tank now, because we ______ run out of gas on the way.

 It’s a very kind offer, but I really _____ accept it. 

Perhaps you ________ stop playing computer games now. Your boss may be turning up in the office at any moment.