完形填空。 Hong Kong has about forty public beaches.1_____ of the beaches are the best in the 2_____. People can 3_____ swimming there. You can go to most of them by  4_____. To get to some beaches, you must take a boat. There are toilets, changing rooms and places to 5_____ food and drink on most of the beaches. You can swim there 6_____ any danger if you remember these instructions (说明): 1. Never swim by yourself (独自). 2. Never swim after a meal or when you feel 7_____or tired. 3. 8_____ stay in the water too long. 4. Never go out in a boat without a life jacket if you can't swim. Remember: A red flag (旗) means that it is 9_____ for anybody to go into the water. A bl ue flag means that it is only dangerous for 10_____. (     )1. A. All (     )2. A. town (     )3. A. go (     )4. A  foot (     )5. A. sell (     )6. A. with (     )7. A. happy (     )8. A. Don't (     )9. A. good (     )10. A. people B. One B. world B. do B. plane B. buy B. before B. sad B. Can't B. dangerous B. teachers C. Some C. place C. have C. bus C. keep C. without C. busy C. Mustn't C. bad C. children D. No D. village D. see D. horse D. eat D. after D. h ungry D. Didn't D. safe D. students