以下对于调节支架高度的说法正确的是（）
A.调节支架高度，使支架上的高度刻度值等于防静电地板的勘测高度值
B.调节支架高度，使支架上的高度刻度值大于防静电地板的勘测高度值
C.按照“先中间，后两侧”的原则，用力矩扳手依次交叉紧固高度锁定螺栓至45N・m
D.按照“先两侧，后中间”的原则，用力矩扳手依次交叉紧固高度锁定螺栓至45N・m
参考答案：A, C
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| It was at a concert that I happened to find David. He was holding his head at a strange 1 as if he were staring down at something. Then the truth struck me. He was blind. The last thing he remembers 2 was his daughter being born. Then the world went 3 . Bad luck is no stranger to this 44-year-old man. His mother died of cancer, and his weak father had to 4 11-year-old David to the care of the state. Things seemed always to go from bad to 5 . Two years ago, his beloved guide dog pulled him out of the 6 of a truck. David was not hurt. The dog 7 . But David does not feel sorry for himself. "These are just little obstacles (障碍) you have to 8 in your life," he said. He has to make a daily two-hour trip to his working place-the X-ray department of an 9 room. It was a hard job to 10 . Before he got it, David was determined to escape the workshop run by the Lighthouse, an organization 11 to help blind people. He wanted a job of developing X-ray film, something 12 , not just he, must do in the dark, including people with 13 eyesight. The Lighthouse called many hospitals, with no result, 14 they offered to pay his first three months' salary. David works alone in a dark room that 15 of chemicals. He cannot wear gloves. 16 , he could not feel. Since this is an emergency room, lives can be put 17 or out of danger. His directress says she trusts him 100 percent. He makes $ 20 000 a year. But his motivation (动机) goes 18 money. "By working, I can actualize my own 19 . That's the most important!" he said. What a shining example for us to 20 ! | ||||
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