may and might are used to talk about possibility.
when they talk about the present or future. they are follwed by a bare infinitive.
when they talk about the past. they are followed by have and a past participle.
must and can not are used to talk about certainty.
must means that we are sure something happens. will happen or did happen and can not means we are sure something does not happen. wont not happen or did not happen.
when thay talk about the present or the future. they are followed by a bare infinitive.
when they talk about the past. they are followed by have and a past participle.
we use the causative form.
to say that we arrange for some body to do something for us.
to talk about an unpleasent action that happens to somebody.
we use have/get+object+past participle.