对二类负荷如何供电。()A、两个独立电源 B、专用线路 C、单回路 D、ABC都对

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问题:

对二类负荷如何供电。()

A、两个独立电源

B、专用线路

C、单回路

D、ABC都对

考点:煤矿供电考试煤矿供电考试题库
题型:多项选择题

如要将100g溶质质量分数为20%的硝酸钾溶液稀释成溶质质量分数为10%的硝酸钾溶液,需加入水的质量为

A.50g

B.90g

C.100g

D.200g

题型:多项选择题

下列哪项是机体缺铁的第三阶段的表现()。

A.血细胞比容下降

B.血清铁蛋白浓度下降

C.游离原卟啉浓度上升

D.运铁蛋白浓度下降

E.以上全是

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Throughout history has (1) changed his physical environment in order to improve his (2) of life. With the tools of technology he has (3) many physical features of the earth. He has (4) woodlands and prairies into farms and made lakes and reservoirs (5) of rivers for irrigation purposes or hydroelectric (6) . Man has also modified the face of the earth by (7) marshes and cutting through mountains to (8) roads and railways.
However, man’s (9) to the physical environment have not always had beneficial results. Today, (10) of the air and water is an increasing danger to the health of the (11) . Each day thousands of tons of gases come out of the exhausts of motor vehicles. (12) from factories pollutes the air of industrialized areas and the surrounding (13) of the countryside. The pollution of water is equally harmful. The whole ecological (14) of the sea is being changed and (15) wastes have already made many rivers lifeless.
Now (16) protection is more pressing than ever before. As we know, massive destruction of the environment has brought about (17) effects and even poses a great (18) to man’s existence. Indifference to these problems will mean committing suicide. Therefore, effective (19) should be taken and laws passed to (20) the environment. Otherwise, man is certain to suffer from the serious consequences caused by this lack of care for his living surroundings.

题型:多项选择题

从物质载体的角度来看,公文可以分为:()、()、()、()。

题型:多项选择题

设备的断路器,隔离开关都在合闸位置,说明设备处在()状态。

A、运行

B、检修

C、设备用

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