我国四大发明中，为欧洲航海家进行环球航行和发现美洲大陆提供了重要条件的是

题干

我国四大发明中，为欧洲航海家进行环球航行和发现美洲大陆提供了重要条件的是（）

A：指南针

B：火药

C：活字印刷术

D：造纸术

上一题下一题 0.0难度选择题更新时间:2019-05-07 06:06:20

A

A. I usually play computer games late at night.

B. I want to buy some music CDs.

C. What's wrong with me?

D. Where do you work?

E. Stand up and do some exercise from time to time.

F. Well, I've got a pain in my back.

G. Do you have breakfast?

A: Can I help you?

B: ____

A: How long have you been like this?

B: Since two weeks ago.

A: Let me have a look. ____

B: I work in an office.

A: Do you play computer games?

B: Yes, a lot. ____

A: Mm, that's it.

B: ____

A: Nothing serious. You spend too much time in front of the computer.

B: What can I do?

A: ____ Don't play computer games too much.

B: OK, I'll take your advice. Thank you.