阅读下列短文，在空白处写出适当的单词，单词的首字母已给出，有的词要注意词形的变化哦！
Swimming is very popular in summer.People like swimming in summer because water （m )people feel cool .If you like swimming and swim in a wrong place,it may not be safe.Last summer ,more than ten people died (w )they were (e )thenselves in the water ,and (m )of them were students .But some people are (s )not careful in swimming. They often think they swim so well that (n )can happen to them in water.Summer is here again,if you go swimming in summer,don't forget that better swimmers have died in (w ).They(d )only because they were not (c ),not because they could not swim. So don't get into water when you go swimming (y ),go with your teachers or your parents. If there is “No (s )"sign,don't get into water,either.If you (r )these,swimming will be safer.