我国为了加强对大气进行环境监测，每天发布空气质量日报，其主要评价指标是（ ）

在平面直角坐标系中有两点A(-2，2)，B(3，2)，C是坐标轴上的一点，若△ABC是等腰三角形，则满足条件的点C有(      )

鲫鱼能在光线很弱的水中游泳，但不会和水中的石块或其他物体碰撞。探究鲫鱼在弱光线下游泳不会发生碰撞是不是先天性行为。

单缸四冲程汽油机工作时，有些冲程是辅助冲程，要靠安装在曲轴上的飞轮的惯性来完成，只有一个冲程是不用靠飞轮的惯性来完成的，这个冲程是（　　）

补全对话

从方框中选择最佳选项完成对话, 有两项多余。

a. I will live in space.

b. What will you do there?

c. Oh, I think life will be better.

d. I will take a spaceship(宇宙飞船)to get there.

e. Will you have a good time there?

f. Maybe everyone will enjoy this life there.

g. Will there be banks, schools and shops?

A: What do you think your life will be like in ten years?

B: ____

A: Where will you live?

B:____ 

A: How will you get there?

B:____ 

A: Will life be interesting there?

B: Yes, I think it will be more interesting.

A:____ 

B: Of course there will be. I think the supermarket will have all kinds of things and we can take anything for free.

A:____ 

B: I agree. People will have a happy life there.