Swimming is one of those activities that can be learned early in life. Little children can learn to swim as soon as they walk. In fact, you need the same skills in walking as in swimming. However, I believe that five is the best age to learn. By five or six, a child knows fear of water, a very important thing to know. It's wise to be afraid, to recognize true danger. Young ones understand that the water can sometimes be very dangerous.      To really benefit from swimming, every swimmer should learn, as soon as possible, these four basic strokes; butterfly, backstroke, Breaststroke, and crawl. I feel that one of these-the breaststroke-is different from the others, since some young swimmers use this stroke naturally, without any training. In swimming there are certain rules every swimmer should follow: 1). Never swim alone! No matter how good you are in the water, don't risk drowning by swimming alone. If you swim by yourself, with no life guards or friends with you, you may get into trouble. 2). Don't go beyond your abilities. Most swimmers know enough not to swim too far from the bank or the beach, Showing off by doing dangerous tricks is no good. Swim safely and you will continue to swim and alive. 3). Don't smoke. Swimming depends on a healthy body; good lungs are part of it. 4). Work at any activity that builds muscles. The author believes that fear of water is  _  .
stupid sensible dangerous not smart