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______.