---I have looked for my keys everywhere, but I can’t find them.
---Sorry to hear that. You _____ them somewhere.
| A．must lose | B．should lose |
| C．must have lost | D．should have lost |
Finally, my thanks go to my tutor, who has offered a lot of suggestions and comments on my paper and ________ every page of my draft.
| A．approved | B．quoted |
| C．polished | D．folded |
（2012浙江卷） According to scientists, our mental abilities begin to______ from the age of 27 after reaching the highest level at 22.
| A．differ | B．shrink | C．fail | D．decline |
（2014届河南省豫东豫北十所名校高三上学期阶段性测试）
I'm really concerned ahout you. If something _______ happen to you call me at once.
| A．would | B．should | C．could | D．might |
（届河南省郑州市第四中学高三上学期第六次调考）
Tony ________ full marks, but he was so careless as to make a spelling mistake.
| A．could have gained | B．can have gained |
| C．must have gained | D．must gain |
（届江西省赣州市六校高三上学期期末联考）
We used to work in the same office and we ________ have coffee together.
| A．should | B．would | C．could | D．might |