—Tom, you look tired this morning. What’s wrong?—I was so busy that I didn’t go to bed _____ 12 o’clock last night.
------I’m taking the driving test next Sunday.------________!
______ trees are cut down in the forests every year.
The population of the world in 20 century became very much _____than that in 19 century.
If I’m free,I’d like to spend ______holiday in Dunhuang.
----_______ do you have out with your friends?----Once a week.