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.
When you see a blue flag you know that ________ there.
A．woman should not swim
B．children should not swim
C．nobody should not swim
D．anybody can swim