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单项选择题

下面半剖视图表达正确的一组是（   ） A. B. C. D.

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单项选择题
Light travels at a speed which is about a million times faster than the speed of sound. In one second, light travels about 300,000 km. But sound travels only 344m. You can get some idea of his difference by watching the start of a race. If you stand some distance away from the starter, you can see smoke comes from his gun before the sound reaches your ears.
This great speed of light gives us some strange facts. Sunlight takes about 8 minutes to reach us. If you look at the light of the moon tonight, remember that the light left the moon 1.3 seconds before it reached you. The nearest star is so far away that the light which you can see from it tonight started to travel towards you four years ago at a speed of nearly 2 million km per minute. In some case, the light from one of tonight's stars started on its journey to you before you were born.
Thus, if you want to be honest, you can say "The stars are shining to night?" You have to say“The stars look pretty. They were shining four years ago but their light has just reached Earth. "
We can know from the information given in the passage that the moon must be about ____ away from us.（　　）
A.onemillionkm
B.350,000km
C.300,000km
D.400,000km
单项选择题
Light travels at a speed which is about a million times faster than the speed of sound. In one second, light travels about 300,000 km. But sound travels only 344m. You can get some idea of his difference by watching the start of a race. If you stand some distance away from the starter, you can see smoke comes from his gun before the sound reaches your ears.
This great speed of light gives us some strange facts. Sunlight takes about 8 minutes to reach us. If you look at the light of the moon tonight, remember that the light left the moon 1.3 seconds before it reached you. The nearest star is so far away that the light which you can see from it tonight started to travel towards you four years ago at a speed of nearly 2 million km per minute. In some case, the light from one of tonight's stars started on its journey to you before you were born.
Thus, if you want to be honest, you can say "The stars are shining to night?" You have to say“The stars look pretty. They were shining four years ago but their light has just reached Earth. "
Sunlight seems to ____ than the light of the moon.（　　
A.havetotravelagreaterdistance
B.movelessquickly
C.travelmuchquickly
D.belesspowerful
单项选择题
北方某地区单层钢结构轻型厂房建安工程单方造价为1000元/㎡，造价由以下三项工程组成：(1)土建工程(包括结构、建筑、装饰装修工程)(2)电气工程(包括强电、弱电工程)(3)设备工程(包括水、暖、通风、管道等工程)问下列哪一组单方造价的组成比例较合理？( )
A.(1)80%；(2)3%；(3)17%
B.(1)60%；(2)20%；(3)20%
C.(1)80%；(2)10%；(3)10%
D.(1)60%；(2)10%；(3)30%
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