2.  talk about possibility and ability
 make requests
 ask for or give permission
subject
auxiliary main
subject + can + main verb
verb
verb
+
I
can
play
tennis.
-
He
cannot
play
tennis.
play
tennis?
can't
?
Can
you
http://www.englishclub.com/grammar/verbs-modals_can_1.htm

3. EXAMPLES
Affirmative
He can play football
Negative
He can’t play football
Interrogative
Can He play football?

4. Affirmative
They can play basketball
Negative
They can’t play basketball
Interrogative
Can they play basketball?

5. Affirmative
She can swim
Negative
She can’t swim
Interrogative
Can she swim?

6. Affirmative
She can play tennis
Negative
She can’t play tennis
Interrogative
Can she play tennis?

7. Affirmative
He can play hockey
Negative
He can’t play jockey
Interrogative
Can he play hockey?

8. Affirmative
They can play
tennis
Interrogative
Can they play
tennis?
Interrogative
They can’t play
tennis