下列变化属于化学变化的是（ ）
A．气密性检查
B．鸡蛋壳中加食醋
C．灯泡通电发光
D．胆矾的研碎
A、检查气密性的过程中没有新物质生成，属于物理变化；
B、鸡蛋壳中的碳酸钙能和食醋中的醋酸反应生成醋酸钙、水和二氧化碳，属于化学变化；
C、灯泡通电发光的过程中没有新物质生成，属于物理变化；
D、胆矾的研碎的过程中没有新物质生成，属于物理变化．
故选B．
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| Health is important to everyone. You should take care of your health. Many people 1 they don't need to take care of their health when they are young. Do they only need to take care of 2 health when they are old? The answer is "No". Many young people die 3 they have health problems. Then, what should you do to keep healthy? First, you must try to drink a lot of 4 every day. Doctors say that people should drink more than eight cups of water a day. It can 5 you away from illness. Remember to do 6 every day. Doing exercise can keep you healthy. It can make you 7 . It is also a good way to help you 8 Eat healthy food. This is one of the best 9 for you to keep healthy. You should try to eat a balanced diet (平衡饮食) every day. Sleeping is also very 10 . When you sleep, you can have a good rest. Getting a good sleep every night can reduce (减少) the chance you fall ill. | |||
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