Scientists are working hard to make possible for people to live on Mars in the future.

Miss Young, thanks a lot for helping me with the problem.— That’s OKJust come to me if you have any questions _______ your study[ ]

How is every thing going in the hospital, dear —_______.

I’m sorry I __________ my homework at home, Mr. Wang! — That’s all right. Don’t forget __________ it to school tomorrow.

It was reported that a little boy undera destroyed house for three days was pulled out alive at last