—You look really tired. ________?—I didn’t sleep well last night. I had a headache.
Mary likes learing English,______ she doesn’t like learning math at all.
------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.