1 Perhaps it will rain later. It may/might rain later. . 2 I'm sure they are not at school now.
3 It's possible that the match will not start before seven.
4 I'm sure she thinks I am not very bright.
5 I know this isn't Robert - he has gone on holiday to Spain.
6 I'm certain the car keys are somewhere in the kitchen.
7 Perhaps the teacher will give us our homework back tomorrow.