2 The bare infinitive is used After the verbs do, does, and dide.g. He does not have her mobile phone.After verbs of perception(see, watch, notice, hear, listen to, feel,smell,etc)After let and makee.g. Let him come in now.After had better, would rather, cannot but, and can do nothing bute.g.. You had better go home.
3 May /MightTo say that it is possible for something to be true now or in the futuree.g. Jane is not here, she may/might be in the library.Jane has not come, but she may/might be here tomorrow
4 For the past May/Might + have +past participle e.g. This is Jane’s umbrella. She may/might have been here this morning.
5 When someone did a wrong thing in the past Should/ought to + have +past participlee.g. You have broken the vase. You should/ought to have been more careful.
6 When we feel sure something is true or not possible e.g. I hear snoring. Tom must be sleeping.For the pastYou looked tired. You can’t have gone to bed last night.