The geography teacher told his students that the earth ______around the sun.

You look very worried. ________ —My mother suddenly got ill yesterday.

It’s always foggy these days in our city. That’s really terrible!— Yes, and I hope to plant trees. ______trees, ______ air pollution.

282. I think they have gone to the airport to _____ their daughter ______.

Thank you for sharing your ruler with me. — _______ That’s what friends are for.