用not…until代替下列句子中的when:
1.     He left the training center when he finished the work.
2.     My friend told me the bad news when I asked him about it.
3.     The young fellow stopped working when his boss asked him to.
4.     The crew will get a rest when they get to the destination.
5.     The plane will take off when the Air Traffic Controller gives out the order.
6.     The stewardesses will start to serve the passengers when the plane starts cruising.
 
 
参考答案:
1.    He didn’t leave the training center until he finished the work.
2.    My friend didn’t tell me the bad news until I asked him about it.
3.    The young fellow didn’t stop working until his boss asked him to.
4.    The crew will not get a rest until they get to the destination.
5.    The plane will not take off until the Air Traffic Controller gives out the order.
6.    The stewardesses will not start to serve the passengers until the plane starts cruising.