–Has Billy finished his homework today–I have no idea. He ______ it this morning.

It is smoggy (雾的) these days. That’s terrible!—Yes, I hope to plant trees. ______ trees, ______air pollution.

The Red Cross goes into areas _______ help is badly needed.

Sorry, Mum! I failed the job interview again.—Oh, it’s too bad. You________ have made full preparations.

It’sso hot today. Why not stay at home and read books— ___________! Let’s read the novel Twilight.