某同学做实验时，如图3连接电路，闭合开关后，灯泡正常发光，但电流表指针不动，电压表读数正常，那么有可能是（      ） 　

下列属于秦岭—淮河一线地理意义的是（    ）

 下列各组溶液中，仅用组内物质就能鉴别出来，且均为无色溶液的是（　　）

   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?