单选题 Passage 2: Hong Kong has about 40 public beaches. Some of the beaches are among the best in the world. People can go there for a swim. You can go to most of them by bus. To go to some of the beaches you must take a boat. There are clothes changing rooms and places to buy food and drink on most of the beaches. You will swim there without danger if you remember these instructions: 1) Never swim alone. 2) Never swim after a meal or when you feel hungry or tired. 3) Don’t stay in the water too long. 4) Never go out in a boat if you can not swim. Remember: A red flag means that it is dangerous for anyone to go into the water. A blue flag means that it is dangerous for children.

单选题 You can do many things on the beaches except ________.

单选题 We can reach ________ by bus.

单选题 When you see a blue flag you know that ________ there.