9 graders: Modal verbs

You mustn't forget certain things, such as: 

- no "s" in the 3rd person singular

- in the interrogative form we need "Inversion" (May I .....?)

- you do not need an auxiliar verb to write the interrogative or the negative forms

- Modal + verb in the infinitive (to)

This table was taken from a book called "Exercícios de Inglês 11º" by Porto Editora.I believe it is an excellent table to synthesize the Modal Verbs.

You can find the explanation and exercises in your book on pages 66, 67 and 175.