They expected that they could solve the problem by________(they).
________(polite),he drove the old man out of the room and shouted at him angrily.
Be careful to cross the street when we meet heavy________(traffic).
My mother can’t sleep well,and sometimes she even stays________(wake)the whole night.
Is it possible for us human beings to leave all the animals in the________ ________(自然环境)?
Some of my friends are interested in________ ________(集邮).