【单选题】
使用直爬梯进行攀登作业时,攀登高度以( )高为宜。___
A. 4m
B. 5m
C. 6m
D. 8m
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答案
B
解析
暂无解析
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【单选题】
施工现场配电母线和架空配电线路中,标志L1___、L2(B)、L3(C)三相相序的绝缘色应是(A)。
A. 黄、绿、红
B. 红、黄、绿
C. 红、绿、黄
D. 黄、红、绿
【单选题】
总配电箱中漏电保护器的额定漏电动作电流I△和额定漏电动作时间T△的选择要求是___。
A. I△>30mA,T△=0.1s
B. I△=30mA,T△>0.1s
C. I△>30mA,T△>0.1s
D. I△>30mA,T△>0.1s,I△•T△≯30mA•0.1s
【单选题】
开关箱中设置刀型开关DK、断路器KK、漏电保护器RCD,则从电源进线端开始其联接次序应依次是___。
A. DK—KK—RCD
B. DK—RCD—KK
C. KK—RCD—DK
D. RCD—KK—DK
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【判断题】
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A. 对
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【单选题】
Read this pasaage and answer the five questions
That people often experience trouble sleeping in a different bed in unfamiliar surroundings is a phenomenon known as the “first-night” effect. If a person stays in the same room the following night they tend to sleep more soundly. Yuka Sasaki and her colleagues at Brown University set out to investigate the origins of this effect.
Dr. Sasaki knew the first-night effect probably has something to do with how humans evolved. The puzzle was what benefit would be gained from it when performance might be affected the following day. She also knew from previous work conducted on birds and dolphins that these animals put half of their brains to sleep at a time so that they can rest while remaining alert enough to avoid predators (捕食者). This led her to wonder if people might be doing the same thing. To take a closer look, her team studied 35 healthy people as they slept in the unfamiliar environment of the university’s Department of Psychological Sciences. The participants each slept in the department for two nights and were carefully monitored with techniques that looked at the activity of their brains. Dr. Sasaki found, as expected, the participants slept less well on their first night than they did on their second, taking more than twice as long to fall asleep and sleeping less overall. During deep sleep, the participants’ brains behaved in a similar manner seen in birds and dolphins. On the first night only, the left hemispheres (半球) of their brains did not sleep nearly as deeply as their right hemispheres did.
Curious if the left hemispheres were indeed remaining awake to process information detected in the surrounding environment, Dr. Sasaki re-ran the experiment while presenting the sleeping participants with a mix of regularly timed beeps (蜂鸣声) of the same tone and irregular beeps of a different tone during the night. She worked out that, if the left hemisphere was staying alert to keep guard in a strange environment, then it would react to the irregular beeps by stirring people from sleep and would ignore the regularly timed ones. This is precisely what she found.
Question1:
What did researchers find puzzling about the first-night effect?
A. What role it has played in evolution.
B. To what extent it can trouble people.
C. What circumstances may trigger it.
D. In what way it can be beneficial. .
【单选题】
Question2:
What do we learn about Dr. Yuka Sasaki doing her research?
A. She found birds and dolphins remain alert while asleep.
B. She found birds and dolphins sleep in much the same way.
C. She got some idea from previous studies on birds and dolphins.
D. She conducted studies on birds’ and dolphins’ sleeping patterns.
【单选题】
在产品只计算材料成本,主要适合于___的产品。
A. 月末在产品数量较大,但各月大体相同
B. 定额资料比较完整
C. 直接材料费用在产品成本中所占比重较大
D. 工资和其他费用发生比较均衡