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Swimming is a good sport. It's popular in summer. People like swimming because the water is cool. But when they swim in a wrong(错误的)place, it is very dangerous(危险的). Summer holiday will be coming. I want to give you some suggestions(建议). First, don't get into the water when you are alone. You should swim with your parents or your friends. Second, don't get into the water if(如果) you see a "No Swimming" sign. Third, you should be careful in the water. If you remember(记住) these, swimming will be safe and it's good for your health.