函数$f\left(x\right)=\left(m^2+3m+1\right)·x^{m^2+m-1}$是幂函数，且其图象过原点，则m=____ 

当地球公转到图中B点位置时，不可能有的现象是（　　）

使我国土地资源遭到严重破坏，耕地减少的最主要自然因素是（　　）

阅读短文，并按要求完成后面的小题。

     Some children are talking about their favorite subjects and activities at school.

     Lucy: I think music is my favorite. I like listening to (听) English songs. I need to relax after a day’s work, so I usually listen to music after dinner.

     Kate: I like music, too. But I only listen to Chinese songs, like Jay Chou’s songs. I also like drawing. I want to be a great painter(画家). I also like taking a walk.

     Peter: I don’t like music or drawing. I like playing basketball. I am a good basketball player. Don’t you think it’s cool?

     Jacky: I am not a good basketball player, but I like running. It is good for my health. I run for half an hour a day. I want to be a running star like Liu Xiang.

     Andy: I am not like many boys. I don’t like sports. I think taking a walk is my favorite. I take a walk for an hour a day.