Fill in the Blanks Modal Verbs Online version Read each sentence and complete with the correct answer. by Susana Patricia Montoya Silva 1 I can should might certain futur must past may could present shouldn't can Must can't can David speak two languages . We use and to talk about someone's skill or general abilities : You eat healthy . It is used to express obligations , . We use , might and to say that something is possible , but not . We use to make general statements about what is possible : We use should and to make suggestions and give advice : You use an uniform . We use could and couldn't to talk about the May ask a question ? ( formal way ) We use when we are not sure about something in the or