We all need to exercise. Doctors say it is good for us. It makes your heart and body strong. It also gives you more energy. And you will feel better yourself. It's best to exercise twice a week. Twenty minutes each time is enough.
   There are many ways to exercise. You can walk, run, play sports, or swim. Many people go to special places to exercise. They are called “fitness centers”. These places have a lot of equitment. Some people buy equitment for their homes. But it is very expensive.Exercising can be fun. Friends can exercise together at fithess center. Or they can play sports together, how do you exercise?

读我国30°N附近甲山坡植被和聚落数量随海拔分布示意图，完成下列问题。

中东是世界上冲突不断的热点地区，产生冲突的主要原因是(     )
①地理位置重要  ②石油资源丰富  ③水资源贫乏  ④宗教矛盾尖锐

阅读选段，完成后面各题。
　　这腰鼓，使冰冷的空气立即变得躁热了，使恬静的阳光立即变得飞溅了，使困倦的世界立即变得(kàng)奋了。
　　使人想起：落日照大旗，马鸣风萧萧!
　　使人想起：千里的雷声万里的闪!
　　使人想起：晦暗了又明晰、明晰了又晦暗、尔后最终永远明晰了的大彻大悟!
　　容不得束缚，容不得羁绊，容不得闭塞。是挣脱了、冲破了、撞开了的那么一股劲!

下列矿石中，其主要成分不属于氧化物的是（   ）