题目内容

deceivedescendanthorizonlayermagnetictwinkleWhat can you see in the night sky? First, look for what appears to be the brightest object. Does it (1)_______ or does it glow? If it glows, it’s probably a planet. If not, it’s probably a star. Most nights the brightest object is the planet of Venus. Look towards the (2) ______ and then look up directly above you, and then back again. But don’t allow Venus to (3) _______ you. In comparison with the stars, it’s bright because it is close.The glow from the (4) ______ of stars in the rest of the sky comes from many light years ago. The light emitted as you gaze at the stars will only be seen by your (5) ____________ many years in the future. Finally, look towards the north to see the North Star. This is of course outside the Earth’s (6) _________ field, so it’s what we call True North.

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1、沸煮法只适用于检验( )对体积安定性的影响。

A.游离氧化镁
B.石膏
C.游离氧化钙
D.三氧化硫

2、进行水泥安定性检测时,调整沸煮箱内水位并将试样放人,然后在( )时间内加热至沸,并恒沸( )时间。

A.30土5min 180土5min
B.45士5min 180士5min
C.30士5min 240士5min
D.45土5min 240土5min

3、水泥安定性仲裁检验时,应在取样之日起__内完成。

A.5d
B.7d
C.10d
D.28d

4、采用沸煮法测定硅酸盐水泥安定性不良的原因是水泥中哪种物质含量过多引起的( )

A.游离态氧化钙
B.化合态氧化钙
C.游离态氧化镁
D.二水石膏

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