Don’t bother your father. He’s got a lot _________ his mind.
The students should wear school uniforms when they’re at school.
Mr. Green is very happy because he is satisfied with his students’ work today.
—What about having a drink? — .
—Mum, summer holiday is coming. I wonder . —How about Qinling Wild Zoo?
—It’s our duty ________our city clean and beautiful. —Yes. We should do something for it.