直流电动机电枢冒烟的原因可能是()。A、长时间过载;B、换向器或电枢短路;C、负载短

题型:多项选择题

问题:

直流电动机电枢冒烟的原因可能是()。

A、长时间过载;

B、换向器或电枢短路;

C、负载短路;

D、端电压过低。

考点:火电电力职业技能鉴定考试电厂电气继电保护初级电厂电气继电保护初级题库
题型:多项选择题

乙烯酮(CH2=C=O)在一定条件下能跟含活泼氢原子的化合物发生加成反应,反应的通式可表示为:

试指出下列反应不合理的是(   )

A.CH2==C==O+HClCH3COCl

B.CH2==C==O+H2OCH3COOH

C.CH2==C==O+CH3CH2OHCH3COCH2CH2OH

D.CH2==C==O+CH3COOH(CH3CO)2O

题型:多项选择题

出汗试验是用于检查()

A.感觉神经有无障碍

B.自主神经有无障碍

C.脑神经有无障碍

D.内脏神经有无障碍

E.运动神经有无障碍

题型:多项选择题

阅读理解

     Few laws are so effective that you can see results just days after they take effect.But in the nine days

since the federal cigarette tax more than doubled-to $1.01 per packsmokers have jammed telephone"quit

lines" across the country seeking to kick the habit.

     This is not a surprise to public health advocates.They've studied the effect of state tax increases for

years, finding that smokers, especially teens, are price sensitive.Nor is it a shock to the industry, which

fiercely fights every tax increase.

     The only wonder is that so many states insist on closing their ears to the message.Tobacco taxes

improve public health, they raise money and most particularly, they deter people from taking up the habit

as teens, which is when nearly all smokers are addicted.Yet the rate of taxation varies widely.

     In Manhattan, for instance, which has the highest tax in the nation, a pack of Marlboro Light Kings

cost $10.06 at one drugstore Wednesday.In Charleston, S.C., where the 7centapack tax is the lowest in

the nation, the price was $4.78.

     The influence is obvious.

     In New York, high school smoking hit a new low in the latest surveys-13.8%, far below the national

average.By comparison,26% of high school students smoke in Kentucky.Other lowtax states have

similarly depressing teensmoking records.

     Hal Rogers, Representative from Kentucky, like those who are against high tobacco taxes, argues that

the burden of the tax falls on lowincome Americans "who choose to smoke".

      That's true.But there is more reason in keeping future generations of lowincome workers from getting

hooked in the first place.As for today's adults, if the new tax drives them to quit, they will have more to

spend on their families, cut their risk of cancer and heart disease and feel better.

1.The text is mainly about  ____ .

A. the price of cigarettes

B. the rate of teen smoking

C. the effect of tobacco tax increase

D. the differences in tobacco tax rate

2.What does the author think is a surprise?

A. Teen smokers are price sensitive.

B.  Some states still keep the tobacco tax low.

C. Tobacco taxes improve public health.

D. Tobacco industry fiercely fights the tax rise.

3.The underlined word "deter"in Paragraph 3 most probably means ___  .

A. discourage  

B. remove

C. benefit  

D. free

4. Rogers' attitude towards the lowincome smokers might be that of ___  .

A. tolerance  

B. unconcern

C. doubt

D. sympathy

5.What can we learn from the last paragraph?

A.The new tax will be beneficial in the long run.

B. Lowincome Americans are more likely to fall ill.

C. Future generations will be hooked on smoking.

D. Adults will depend more on their families.

题型:多项选择题

企业进行HSE管理的目的之一是()。

A、满座顾客的一切需要

B、保证员工的健康与安全,保护企业的财产不受损失

C、建立应急准备与相应计划和程序

D、对职业健康安全绩效进行常规监视和测量

题型:多项选择题

防止柱状晶搭桥的措施有()。

A.低过热度浇注

B.加入形核剂

C.凝固末端强制冷却

D.电磁搅拌

更多题库