The bike hit the tree ______ I could get off.
A when             B before            C until            D while

After reading a book or a magazine in the reading room , put it back_____it was.

. The school of the future will probably be quite different from_____they are today.

．We should give a hand to the people ________ need help．

.That’s such a good radio _____ almost every one wants to buy ____people can pick up many channels about the world..

. They traveled on horseback for many days and reached ______ is now Gum Tree.

Peace and development are not only the goals of China, but also the most meaningful direction _____ the whole world should take.

Each player of chess is trying to trap the other player’s king into a position _________
escape is impossible.

Bad habits, _________ formed, are difficult to get rid of.

–---Dear me! I’ve been in America for a month.
-----________ you are settled, why don’t you take up some serious study ?