根据短文内容选择最佳答案。Hong Kong has about forty public(公共的) beaches. Some of the beaches are among the best in the world. People ` can go there for aI swim. You can go to most of them by bus. To go to some beaches, you must take a boat. There are toilets, changing rooms and places to buy food and drinks on most of the beaches.
Here are some suggestions to keep safe in the water:
Never swim alone.
Never swim after a meal or when you feel hungry or tired.
Don't stay in the water too long.
Never go out in a boat if you can't swim.
Remember: A red flag means that it is dangerous for anybody. Everybody shouldn't go into the water. A blue flag means that it is dangerous for children.