Vitamin C helps our bodies make a special chemical, which __________ affects our brains, making us feel happy.
| A．in all | B．in turn |
| C．in advance | D．in short |
Once you ______ the habit of smoking, it is hard to quit.
| A．get over | B．get into | C．get through | D．get up |
It's high time that you ________ even harder at your lessons as the exam is around the corner.
| A．work | B．will work | C．worked | D．have to work |
The center, dealing with children_______ to computer games, has achieved great success.
| A．addict | B．addicting | C．to addict | D．addicted |
—How I wish I had studied harder when I was in senior school! —If you had，you ________ a university student now.
| A．are | B．would be | C．should | D．were |
With so much work on hand, you _____ to see the game last night.
| A．mustn’t go | B．shouldn’t go | C．couldn’t have gone | D．shouldn’t have gone |