按电路中流过的电流种类可把电路分为（）和交流电路两种。

     When I was a boy, each of my holidays seemed wonderful. My parents took me by train or by car to
a hotel by the    1   . All day I played on the sands with strange excited children. We made houses and
gardens, and    2    the tide (潮水) destroy them. When the tide went out, we    3    over the rocks and
looked down at the    4    in the rock pools.
     In those days, the sun seemed to shine always brightly    5    the water was always warm. Sometimes
we left beach and walked in the country,    6    destroyed houses and dark woods. There were sweets in
one's pockets or good places one could buy ice creams. Each day seemed a lifetime.
     Though I am thirty-five years old, my    7    of good holiday is much the same as it was. I still like the
sun and warm sand and the sound of waves beating the rocks. I never wish to build any sand house or
sand garden     8   , I love the sea and often feel sand running through my fingers.
     Sometimes I wonder what my ideal    9    will be like when I am old. All I want to do then, perhaps, will
be to lie in bed, reading books about children who make houses and gardens with sand, who watch the
incoming tide, who make themselves    10    because of too many ice creams.