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问题 单项选择题

螺纹标记中的旋合长度代号，对于梯形螺纹和锯齿形螺纹来说分（）组；一般情况下，按（）旋合长度考虑，不加标注。

A.三/长

B.三/短

C.二/长

D.二/中等

答案

参考答案：D

选择题

生活中常常碰到涉及化学知识的某些问题，下列叙述正确的是（        ）

①人的皮肤在强紫外线的照射下将会失去生理活性

②米酒变酸的过程涉及了氧化反应

③棉花、人造丝和蜘蛛丝的主要成分都是纤维素，充分燃烧时只生成CO2和H2O

④蜂蚁叮咬人的皮肤时将分泌物甲酸注入人体，此时可在患处涂抹小苏打或稀氨水

⑤用苯酚对食物进行消毒是国家允许的

A．①②③④

B．①③④⑤

C．①②④

D．②④⑤
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填空题

When I was growing up, I was embarrassed to be seen with my father. He (1) severely crippled and very short, and when we would walk together, his hand on my arm (2) balance, people would stare. I would inwardly be afraid (3) squirm at the unwanted attention. If he ever noticed or was bothered, he never let (4) .
It was difficult to coordinate (5) steps - his halting, mine impatient - and because of that, we didn’t say much as we went along. But as we started out, he always said, "You (6) the pace. I will try to adjust to you. "
Our usual walk was to or (7) the subway, which was how he got to (8) . He went to work sick, and (9) nasty weather. He almost never missed a day, and would (10) it to the office even if (11) could not: a matter of pride!
He never talked about himself as an object of pity, (12) did he show any envy of the more fortunate or able. What he looked for in others was a "good heart", and if he found one, the owner was good enough for him.
Now that I am older, I believe that is a proper standard (13) which to judge people, even though I still don’t know precisely (14) a "good heart" is. But I know the times I don’t have one myself.
He has (15) gone many years now, but I think (16) him often. I wonder if he sensed my reluctance to be seen with him during our (17) . If he did, I am (18) I never told him how sorry I was, how unworthy I was, how I regretted it. I think of him when I complain about trifles, when I am (19) of another’s good fortune, when I don’t have a "good heart".
At such times I put my hand on his arm to regain my (20) , and say, "You set the pace, I will try to adjust to you.\
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