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问题 填空题
cos45°•tan45°+
3
tan30°-2cos60°•sin45°=______．
答案

∵cos45°=

2
2
，tan45°=1，tan30°=
3
3
，cos60°=
1
2
，sin45°=
2
2
，

∴cos45°•tan45°+

3
tan30°-2cos60°•sin45°，

=

2
2
×1+
3
×
3
3
-2×
1
2
×
2
2
，

=1．

故答案为：1．

单项选择题

在《论灵魂》一书中，亚里士多德将人的生命对应于( )

A．营养的灵魂

B．感觉的灵魂

C．理性的灵魂

D．非理性的灵魂
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单项选择题

Americans use more water than any other people in the world. If we continue to use water at the rate we do now, we will soon not have enough to meet our needs. In 1980, 40 billion gallons were used each day in the United States. In 1990, 700 billion gallons were used. The average Americans uses almost 90 gallons of water a day for personal use. And much move water is needed to make the things American people like to have. For example, it takes thousands of gallons of water to make one pound of beef for the dinner table. It takes more than 100,000 gallons of water to make a car. If we include these uses of water, the average American uses about 2000 gallons of water a day.

Which is not true according to the passage

A．Americans may run short of water in the future.

B．Americans use more water than ever.

C．Americans use as much water as they used to.

D．The more things Americans like to have, the more water is neede
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