If a man in a spaceship looked down at the Earth, he would see mainly water．He might think that the Earth was one giant ocean with little land．
Nearly seven-tenths of the Earth's surface is covered by water．One ocean, the Pacific(太平洋), has an area of 63 million square miles．
Many years ago people thought that the land under all this water was flat．Now they know that this is not true．There are as many mountains under the sea sa there are on the land．
At first, there was very little salt in the sea．The salt was brought into the sea by rivers．It is possible to measure the age of the earth by measuring the amount of salt in the sea．Scientists can calculate how many years it took for this amount of salt to be carried from the land into the sea．
(1)
Nearly ________ of the Earth's surface is covered by water．
[ ]
A．
seven-tenths
B．
three-tenths
C．
seven-tenth
D．
three-tenth
(2)
Long time ago people thought that the land under the sea was ________．
[ ]
A．
mountains
B．
a ball of gas
C．
full of coal
D．
flat
(3)
In fact, under the sea the land ________．
[ ]
A．
is full of mountains
B．
is almost flat
C．
is full of coal
D．
is a ball of gas
(4)
At first, there was ________．
[ ]
A．
a little salt in the sea
B．
much salt in the sea
C．
little salt in the sea
D．
no salt in the sea
(5)
We can know the age of the Earth by measuring ________．
Small children often laugh at(嘲笑)a lame(瘸子)or a blind person, or at someone who isn't dressed as well as they are．But as they grow up, they learn not to hurt people's feelings by laughing at their problems．They learn to laugh at other things．Most important, they learn to laugh at themselves．
Suppose(假设)you're playing a game．You make a mistake and lose．Do you become angry? Or can you laugh at yourself and hope to do better next time?
Suppose you're at a special dinner．You spill(溢出)some food．Why keep worrying? Why not laugh it off and enjoy yourself anyway? If you can, it's a good sign you have grown up．
(1)
This passage is about ________．
[ ]
A．
why laughter is good for your body
B．
what you should laugh at
C．
when babies learn to laugh
D．
where you may laugh
(2)
The writer says small children laugh at people who ________．
[ ]
A．
have problems
B．
spill food
C．
dress well
D．
play games
(3)
The writer shows how laughter could help you not to ________．
[ ]
A．
make a mistake
B．
lose a game
C．
become angry
D．
try again
(4)
Next the writer shows how laughter could keep you from ________．
[ ]
A．
spilling food
B．
worrying
C．
enjoying yourself
D．
growing up
(5)
If you find a new skill(技能)hard to learn, you should ________．
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