I can’t find my ticket. I think I must have lost_____.
--- Would you like _____ camp with me?--- I’d like to. But I am busy ______ my homework.
--- Lin Tao, can I use your English dictionary?--- Sure. But you _______ return it before the class.
--- What do you think of pollution of the big factory?--- It’s a serious problem. We should _____ all the people to do something for it.
There is little water in your cup, ________?
--- What are you doing here, Mrs. White?---I'm waiting for my son. He________ back from school.