I felt it hard to keep up with my classmates. But whenever I want to_ _, my teacher always encourages me to work harder.
| A．go on | B．run away |
| C．give up | D．give back |
--_________ I come back before five o’clock?
--No, you________. But you can’t be back later than seven o’clock.
| A．Need, must | B．may, mustn’t |
| C．Can, can’t | D．Must, needn’t |
---Must I tell Mike about it?
---No, you _______. He’s already been told.
| A．mustn’t | B．can’t |
| C．needn’t | D．shouldn’t |
We brush our teeth twice a day.
| A．may | B．can | C．should | D．shouldn’t |
My mother is ill. I ______ stay at home to take care of her.
| A． can | B．may | C．have to | D．maybe |
—Is Mr. Smith over there?
—It ________ be him. He has gone to Beijing on business.
| A．can't | B．must | C．might | D．can |