Ответ:
Ex.1
1) .
2) ?
3) !
4) ?
Ex.2
1) I can not wash the floor.
2) Can they watch TV?
3) She can look at me.
Ex.3 (can't = cannot). Can't - это краткая форма, а Cannot полная!!!
1) The girl can't open the door.
2) We can't play tennis.
3) She can't phone me.