7．
完形填空
Time is very important to us. When and by
whom were the watches or clocks 1 Perhaps nobody knows. How could we tell time
if there were no watches or clocks anywhere in the world?
The2 was probably the world's first "clock",
except in the far north, where the Eskimos live. There, it's dark most of the
winter, and 3 most of the summer. But 4 most of the world, people have used the sun
for day. 5 you don't have a clock that shows time, you
still know that when the sun shines, it's day, and that when it's dark, it's
night. The sun can not only tell you whether it's day or night but also tell
you whether it's morning, noon, or afternoon. When the sun is almost directly overhead,
it's6.
People who live near the sea know time from
the tides (潮汐). In the daytime, for about six hours,
the water rises 7on
the beach. The same thing 8again
at night. There are two high tides and two tides every 9 hours.
In some places in the world the wind comes
up at about the same time every day or changes direction or stops 10.
In these places the wind can be the clock.
