If I ask my children to do something a lot of different things may happen: They could do it , they might do it, they ought to do it, they must do it, they should do it.
There are lots of ways to describe how things can be done,. The experts call these modal verbs. The important ones are can , should, might, may, have to, could, and will.
For example, if I ask my daughter or my husband to wash up there are several possibilities:-
He can do it. There is no real reason why not. There is plenty of hot water and lots of dirty dishes.
She should do it. It’s her turn and she has to take some responsibility.
He might do it. It’s a possibility.
She may do it. There’s a chance she will do it, she certainly has my permission to do so.
She will have to do it, because I will insist that she does, and I am not going to do it for her.
He will do it. He’s a reasonable person and knows the job needs doing. This refers to an action in the future. At some point in the future he will do the washing up, it's a promise.
She could do it. She is old enough and careful enough to do the job properly. This doesn’t necessarily imply she will do it. She might protest that it isn’t her turn, or that she is watching television, or she didn’t eat as much as us, and a whole host of other excuses that I’ve heard over the years.
Now you try:-
Write some sentences about going swimming. Try to use each of the modes. There are some ideas below, but you should come up with your own.