Not until the teacher explained the importance of getting up early ______ we promise to come early.
| A．should | B．would | C．did | D．could |
Experts warn that medical waste from hospitals, ifproperly, may contribute to spreading diseases．
| A．not handled | B．not being handled |
| C．not to be handled | D．not having been handled |
—Whyso early? The movie doesn't start till seven．
—I don't want to be at the traffic there．It's terrible during the rush hour．
| A．have you left | B．do you leave | C．would you leave | D．are you leaving |
If itthe climate, I would stay here much longer．
| A．is not for | B．had not been for | C．were not for | D．would not be for |
Sinking in the cheers of people, David walked off the stage, tears droppinghe could stop them．
| A．after | B．when | C．until | D．before |
Days of snowstorms have left the cityunder thick layers of ice and some 50,000 homes without power．
| A．to be trapped | B．trapped | C．having trapped | D．being trapped |