若a、b、c为实数，且a+b+c=1，则a²+b²+c²的最小值为____ 

设集合$M=\left\{x|x=\sin \frac{n\pi }{3},n\in Z\right\}$，则满足条件$P\cup \left\{\frac{\sqrt{3}}{2},-\frac{\sqrt{3}}{2}\right\}=M$的集合p的个数是（   ）

我国是世界四大文明古国之一。目前世界上发现原始人类遗迹最多的国家是（    ）

读句子，选择恰当的答语。

How many crayons do you have?____   a. Yes, it is.

Look at my new crayons! ____               b. I can see 12.

Is it in your toy box?____                       c. I have 16.

Do you like apples?____                        d. Oh, how nice!

I don't like watermelon. ____              e. No, I don't.

How many kites do you see? ____         f. Me, neither.

Let's buy some fruit____                      g.OK!