电学课中，老师曾讲过“水果电池”，激发了某同学对苹果导电性能的探究，因为电路中电

    All over the world people swim for fun. Swimming is enjoyed by people of 1 ages, from the very
young to the very old. There are many places for people to swim in swimming pools. Many schools,
hotels and clubs have swimming pools. Some people have pools of 2 in their yards.
    Swimming is one of 3 forms of exercise. It can 4 hearts and bodies strong. It can also help blood
circulate(循环). Handicapped(残疾的)people can keep their bodies in better condition by swimming 5
they can't enjoy sports.
    6 is a good idea for parents to see to it(务必做到) that their children learn to swim 7 an early age.
So their children will 8 it for the rest of their lives.
    There are many rules for water safety. These rules can help save not only your life 9 the life of a friend. 
 First of all, know 10 . Many schools 11 wimming lessons to children. Adults(成人) can learn to swim at
public pools. 12 rule to remember is never to swim 13. Always swim with a friend and know 14  in the
water at all times. It is best to swim 15in safe places if you are beginners. If every one learned to swim
and obeyed the rules for water safety, most drawing(溺水) could be avoided.