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问题 单项选择题

焦炉煤气和高炉煤气的爆炸极限（按体积计算）分别为（）。

A．COG6-30，BFG46-68

B．COG6.3-27.0，BFG20-74

C．COG46-68，BFG6-30

答案

参考答案：A

单项选择题

维生素B1（）。

A．遇酸容易脱水生成脱水产物

B．与空气长期接触遇光氧化生成硫色素

C．体内代谢磷酸化后生成黄素单核苷酸

D．有吡多醇(吡多辛)、吡多醛、吡多胺三种形式

E．容易被氧化生成多聚糠醛，这也是其变色的主要原因
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单项选择题

Are you a man or a mouse When people ask this question they want to know (1) you think you are a (2) person or a coward. But you will never really know the answer to this question (3) you are tested in real life. Some people (4) they are brave but when they come face to face with real (5) , they act like cowards. Others think of themselves as cowards, but when they meet danger, they act like (6) .Lenny had always thought of himself as a (7) person. He got worried before examinations. He worried about his job and health. All he wanted in life was to be safe and healthy. (8) , on January 15th, 2002, a plane crashed into the Potomac River in Washington. Lenny went to the river to See what was happening. He saw a woman in the (9) water. Lenny did not feel afraid. He kept very (10) and did a very dangerous thing. He jumped into the Potomac, (11) to the woman, and kept her head (12) the water. Seventy-eight people died that day. Thanks to Lenny, it was not (13) .When you are in a very (14) situation and feel afraid, the body automatically produces a chemical in the blood. The chemical is called adrenalin. (15) adrenalin in the blood system, you actually feel per and per and are (16) to fight or run away. However, when you are absolutely terrified, the body can produce too much adrenalin. Where this (17) , the muscles become very hard and you find you (18) move at all. You are then paralyzed with fear. This is (19) when we are very frightened, we sometimes say we’re "petrified". This word comes from the Greek word "petros", which means "stone". We are (20) frightened that we become stonelike.

 

第（17）空应选择（）

A．gets

B．disappears

C．happens

D．goes
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