问题
单项选择题
光学分度头避免了蜗轮副制造误差对测量结果的影响，所以具有较高（）。
A.装配精度
B.位置精度
C.测量精度
D.相对精度
答案
参考答案：C
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光学分度头避免了蜗轮副制造误差对测量结果的影响，所以具有较高（）。
A.装配精度
B.位置精度
C.测量精度
D.相对精度
参考答案：C
| 完形填空。 | ||||
| Recently, I flew to Las Vegas to attend a meeting. As we were about to arrive, the pilot announced with apology that there would be a slight 1 before setting down. High desert winds had 2 the airport to close all but one runway. He said that we would be 3 the city for a few minutes waiting to 4 . We were also told to remain in our seats meanwhile with our seat belts fastened 5 there might be a few bumps (颠簸). Well, that few minutes turned into about four-five minutes, including a ride that would make a roller coaster (过山车) 6 by comparison. The movement was so fierce that several passengers felt 7 and had to use airsickness bags. As you might guess, that's not good thing to have happen in a(n) 8 space because it only 9 to increase the discomfort of the situation. About twenty minutes into the adventure,the entire airplane became very 10 . There was now a sense of anxiety and fear that could be 11 noticed. Every passenger simply held on for dear life…except one. A 12 was having a good time! With each bump of the 13 , he would let out a giggle (咯咯的笑) of delight. As I observed this, I 14 that he didn't know he was supposed to be afraid and worried about his 15 He neither thought about the past nor about the future. Those are what we grown-ups have learned from 16 . He was 17 the ride because had not yet been taught to fear it. Having understood this, I took a deep breath and 18 back into my seat, pretending I was 19 on a roller coaster. I smiled for the rest of the flight. I even 20 to giggle once or twice, much to the chagrin (懊恼) of the man sitting next to me holding the airsickness bag. | ||||
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