短文填空。阅读下则短文，然后在空白处写出适当的单词，单词的首字母已给出。
（注意：共有12个空供你选做，注意词形的变化。）
Swimming is very popular in summer. People like swimming in summer because water (1)m______
people feel cool. If you like swimming and swim in a wrong place, it may not be safe (安全的). Last
summer, more than ten people died (2)w______ they were (3)e______ themselves in the water, and
(4)m______ of them were students. But some people are (5)s______ not careful in swimming. They
often think they swim so well that (6) 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 (7)w______. They
(8)d______ only because they were not (9) c______, not because they could not swim. So don't get
into water when you go swimming (10)y______, go with your teachers or your parents. If there are
"No (11)S______" sign, don't get into water, either. If you (12) r______ these, swimming will be safer.