选出能对每个句子做出适当反应的答语（  ）

下列实验能够用于直接验证质量守恒定律的是（   ）

补全对话。在横线上填上一个适当的句子，使对话完整、通顺、正确。

W: Good morning, young man.____

M: I feel weak and I've got a bad headache.

W: ____

M: No, I don't have a fever. I have taken my temperature. It's all right.

W: How about your sleep?

M: Terrible! I dream a lot and I always feel tired the next morning.

W: ____

M: I am playing computer games these days. And I play till late at night.

W: I see. You play games too much.

M: ____

W: You should not do that any more first. Then relax a little, have a warm bath and lake this medicine for a week. It will help you.

M: Thanks, doctor. ____ 

W: Three times a day.

M: OK. Thank you. Bye!