Military helicopters dropped food and medicine to the earthquake survivors that remained ________ in remote mountain villages.
| A．cut off | B．paid off |
| C．put off | D．laid off |
______I be free tomorrow，I could go with you．
| A．Could | B．Should | C．Might | D．Must |
______stopping polluting the earth______hope to live in a better environment．
| A．Only to；we Call | B．Only to；can we | C．Only by；can we | D．Only by；we can |
You______be tired—you've only been working for an hour．
| A．must not | B．won't | C．can't | D．may not |
Father______for London on business upon my arrival，so I didn't see him．
| A．has left | B．left | C．was leaving | D．had left |
The success of this project______everyone making an effort．
| A．relies on | B．cares for | C．reminds of | D．suffers from |