摆脱电流是人能自主摆脱带电体的最大电流,人的工频摆脱电流约为10A。

题型:判断题

问题:

摆脱电流是人能自主摆脱带电体的最大电流,人的工频摆脱电流约为10A。

考点:低压电工考试低压电工考试题库
题型:判断题

(8分)现有①KMnO4 ②H2 ③O2 ④CL2 ⑤CO ⑥AL 六种物质,从氧化性、还原性的角度分类,若将常用的氧化剂放入甲:_____ 中,常用的还原剂放入乙:_____中,则:

⑴甲中有       ;乙中有       。(填序号)

⑵由Fe Fe3O4 ,Fe2O3Fe 可知,欲实现I反应过程应从___________ (填“甲”或“乙”,下同)中找物质,欲实现II反应过程应从        中找物质。

⑶请将4种物质:Fe、Fe2O3、CO、CO2分别填入下面对应的横线上,组成一个配平了的化学方程式,并标出电子转移的方向和数目。(提示:反应物是Fe2O3和3 CO )

+           ="====             " +                   

⑷一氧化氮是工业制硝酸的中间产物,生成一氧化氮的化学方程式为:

4X+5O2 4NO+6H2O,则根据质量守恒定律可以推出X的化学式为        。

题型:判断题

下列哪一项不是打开文件时所做的工作?

A.填写文件控制块中的文件读写方式项

B.检查文件名所对应的文件控制块是否已调入内存

C.检查操作的合法性

D.返回给用户一个文件描述符

题型:判断题

The most common disease in the world is the cold. It often starts with a sore throat(咽部疼痛). You sneeze (打喷嚏) and your nose runs. You usually have a headache, too. Often you have a cough later. It's not a serious disease, but you can feel quite bad.

There isn't a cure (良药 ) for a cold, but you can take medicines to make you feel better. For example, you can take aspirin (阿司匹林) to get rid of your headache. It is good to rest, and to drink a lot of water, too. A doctor once told me, "With the right medicine, a cold will last for seven days. With no medicine, it will go on for a whole week!"

Where does our medicine come from? A long time ago, people understood that some plants made them feel better. They ate the leaves, the roots , the fruit or the seeds  of plants. For example, the juice of lemons (柠檬) makes a sore throat feel better. In modern times, scientists have looked at these plants, and found out which chemicals (化学药品) are in them. Many of our medicines today are made from those chemicals. There are some diseases that we can't cure yet. And nobody has found a cure for old age. But because of modern medicines, the average (平均的) person now lives longer than their grandparents.

1. A cold often starts with________________.

A. a headache     B. a cough   C. a pain in your throat    D. feeling a little cold

2. What should we do when we catch a cold?

A. We only take some medicine.

B. We should rest well, drink much water and have some medicine.

C. We just wait for a whole week.

D. We only need a good rest.

3. What makes a sore throat feel better?

A. The medicine aspirin.          B. A lot of water.

C. Something inside lemons.       D. The root of a plant.

4. What is the real meaning of the doctor's words?

A. There is almost no medicine that can cure the cold.

B. There is some medicine that can cure the cold.

C. You will feel well after a week when you take some medicine.

D. The cold is a serious disease.

题型:判断题

点火系统中控制的几个要素是()

A.分电器、闭合角

B.提前角、点火头

C.提前角、闭合角、爆震控制

D.通电时间、爆震控制

题型:判断题

手机上网中出现的“让家长头痛的新问题”,说明在文化生活中仍然存在令人忧虑的现象。对此,作为学生应该()

A.加强对手机网络的管理,正确取舍信息

B.提高辨别不同性质文化的眼力,增强抵御能力

C.取其精华,去其糟粕,推陈出新,革故鼎新

D.远离网络,防止不良信息对自己的消极影响

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