Three more verbs you'll need every day:

Pronoun	Poder (can, may)	Saber (to know)	Dizer (to say, to tell)
eu	posso	sei	digo
você / ele / ela	pode	sabe	diz
nós	podemos	sabemos	dizemos
vocês / eles / elas	podem	sabem	dizem

Once again the trouble sits mostly in the eu form — posso, sei, digo — plus diz, which drops its -e just like faz and quer. Everything else takes the regular -er endings you already know.

Like querer, poder and saber are followed by a plain infinitive: Eu posso ir. — I can go.