Resposta:

Hello!! o/

Present Tense:

1) I can ride a bike.

2) She can do what you want.

3) They can stay with me.

Past tense:

1) He could help you.

2) I could bring it.

3) We could do everything.

Negative form:

1) I can't play the piano.

2) You can't download it now.

3) She can't sing very well.

É isso aí!! Espero ter ajudado! ^^