16．It is usually not quite cold in this area in March，but sometimes temperature_______low．
| A．should | B．must | C．can | D．Shall |
---What will you do next Sunday?
---Maybe do some shopping, for I ______ go to school on Sunday.
| A．mustn’t | B．can’t | C．don’t have to | D．had better not |
As we all know, no one is perfect, and everyone has his own ______.
| A．mistakes | B．weakness | C．tricks | D．benefits |
It was playing computer games that cost the boy plenty of time that he ______ have spent studying.
| A．might | B．must | C．could | D．ought to |
After released(释放) from prison, the young man ______ a living by running a small restaurant.
| A．produced | B．formed | C．earned | D．performed |
---It’s a long time since I saw my parents.
---______ them this weekend?
| A．Why not to visit | B．Why not visit | C．Why not visiting | D．Why don’t visit |