电缆与热管道及热力设备平行、交叉时,应采取隔热措施,使电缆周围土壤的温升不超过()A

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问题:

电缆与热管道及热力设备平行、交叉时,应采取隔热措施,使电缆周围土壤的温升不超过()

A.15℃

B.20℃

C.30℃

D.10℃

考点:高校实验室安全考试电气电气题库
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扬声器是将声能转换为电能的换能器件。( )

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Ted lives in a big city .Today he's very happy .it's the first day of school .Ted to go back to school. He wants to see his friends. He is going to meet his new teachers.

Ted gets up early in the morning .He washes and puts on his new clothes .Look !He is having breakfast with his parents .Now ,he is ready for school.

He goes to school by bike .He meets his friends outside the school gate .They are talking about something .Then the bell (铃声)rings .(铃响)Everyone runs to his or her classroom.

小题1:Where does Ted live!

A.He lives in a small house.

B.He lives in a big city .

C.He lives on a farm.

D.He lives in a school.小题2:Does Ted want to go back to school?

A.No,he doesn't

B.Yes ,he wants .

C.Yes ,he does .

D.Yes ,he doesn’t.小题3:Who does he want to see ?

A.His friends

B.His brother

C.His father

D.His mother小题4:Who is he having breakfast with?

A.His father

B.His brother

C.His mother

D.His parents.小题5:How does Ted go to school ?

A.He goes to school by bus

B.He goes to school by bike .

C.He goes to school by car

D.He goes to school on foot .(步行)

题型:单项选择题

真菌、细菌等微生物在生态系统中占重要地位,这是因为

A.吸收代谢废物

B.能为其他生物提供食物来源

C.能分解有机物,使之变为无机物,供绿色植物再利用

D.吸收二氧化碳,释放氧气

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某患者外周血涂片如图,请问下列哪种是促成这种聚集最强有力的物质()

A.白蛋白

B.甘油三脂

C.γ球蛋白

D.纤维蛋白原

E.胆固醇

题型:单项选择题

螺旋桨的桨叶角增大叫(),发动机启动时螺旋桨在()。

A.变大距,低桨叶角

B.变小距,低桨叶角

C.变桨距,高桨叶角

D.变几何桨距,高桨叶角

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