根据句意及首字母补全在本课中出现的单词。

1. Mr White gives us some good a ______.

2. Can you s______ your name, please?

3. Please give us a r______ quickly.

4. I don't know which book to c______.

5. D______ is a kind of valuable stone.

6. There is n______ in the classroom.

7. Easy is the o______ of difficult.

8. You need to eat a lot of v______.

火花塞产生电弧点燃压缩过的燃料和空气的混合物进行燃烧，燃烧气体膨胀推动活塞向下运动，被称为（）。

A.正常燃烧

B.爆燃

C.非正常燃烧