You _______ wash your hands before meals. It is good for your health.
| A．may | B．can |
| C．have better | D．should |
In the past few years there _________great changes in my hometown.
| A．have been | B．were | C．had been | D．are |
--- Don’t step on the grass next time, Mike.
---________.
| A．Is that so? | B．Don’t worry. | C．No, I don’t | D．Sorry, I won’t |
They _______ in Nanjing since they came to China two years ago.
| A．lived | B．have lived | C．live | D．are living |
I don’t know when my son ________ back. When he_________ back, I’ll call you.
| A．comes, comes | B．will come, will come |
| C．comes, will come | D．will come, comes |
---Must I finish doing my homework now, Mum?
---No, you ________.
| A．can’t | B．may not | C．mustn’t | D．needn’t |