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 a 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.      
                  You will swim there without (没有)  danger if you remember these instructions:      
                 1. Never swim alone(单独) .      
                 2. Never swim after a meal or when you feel hungry or tired.      
                 3. Do not stay in the water too long.      
                 4. Never go out of a boat if you can't swim.      
        Remember:A red flag means that it is dangerous for anybody to go into the water. A blue flag means that it is dangerous for children.

A. all the public beaches     
B. any public beaches     
C. only a few public beaches     
D. all the public beaches except some

A. something about Hong Kong's beaches and swimming there
B. that swimming in Hong Kong is dangerous  
C. that Hong Kong has many best beaches in the world  
D. it is not easy to go swimming in Hong Kong