用适当的词填空。

1. I often help Mary         her Chinese.  

2. The vet takes care of all kinds         animals.  

3. There         a lot of orange in the bottle.  

4.         girls and boys in the USA enjoy playing the game.  

5. I have some news         you.  

6. There         any storybooks in my bag.  

7. Are there         desks and chairs there? Yes , there are a lot of.  

8. There      some white sheep under the tree.  

9. I have two new friends.  One is from Britain.                 is from Japan.  

10. Now, let's do it         group.  

关系数据库的规范化理论指出：关系数据库中的关系应满足一定的要求，最起码的要求是达到1NF，即满足( )。

A．每个非码属性都完全依赖于主码属性

B．主码属性惟一标识关系中的元组

C．关系中的元组不可重复

D．每个属性都是不可分解的