---Would you like some more beef?
---No, thanks. I’m ______ a diet.
| A．for | B．to | C．on | D．in |
There are some health problems that, when in time, can become bigger ones later on.
| A．not treated | B．not being treated |
| C．not to be treated | D．not having been treated |
Bears fat stores throughout the summer and fall to have energy enough to last them through their winter sleep.
| A．pack up | B．build up | C．bring up | D．take up |
Half of surveyed in 16 countries say they go first to their closet friend to share their deepest wishes and darkest fears.
| A．these | B．some | C．ones | D．those |
Nothing could be done, he_____ absent.
| A．was | B．being | C．to be | D．be |
He ________ the exam, but he was too careless.
| A．could have passed | B．couldn’t have passed |
| C．must have passed | D．may have passed |