4. Third person (singular)
IRREGULAR VERBS
· be --> is He is a boy ( You cannot say bes!)
· have --> has She has a dog ( You cannot say haves!)
MODAL VERBS
Such as can, must, should, may and might, do not take -s in the third person singular present because, modal verbs do not take endings at all.
· She can speak three languages.
He must like football a lot