19世纪末20世纪初欧洲实施的学制主要是（） A.单轨制 B.双轨制 C.分支型学制

变电检修工应自行掌握的电气测试有：绝缘电阻、接触电阻、直流电阻的测试和动作特性的试验。

阅读理解。

     You've probably heard countless times how exercise is "good for you", but do you know that it can

actually help you feel good, too? Getting the right amount of exercise can speed up your energy levels

and even help you to feel better emotionally.

     However, like all good things, it's possible to overdo on exercise. Although exercising is a great way

to maintain a healthy weight, exercising too much to lose weight isn't healthy. The body needs enough

calories to function properly. Remember that you're still growing and will continue to do so throughout

your teen years. You'll need the energy to fuel the growth.

     Exercising too much in an effort to burn calories and lose weight can be a sign of an eating disorder.

If you have any doubts about how much you should be exercising, talk with a school nurse or family

doctor. And if you ever get the feeling that your exercise is in charge of you rather than the other way

around, talk with your doctor, a parent, or another adult you trust.

     Considering the benefits to the heart, muscles, and mind, it's easy to see why exercise is wise. If you

exercise now, keep it up as you become an adult (this is often the biggest exercise challenge for people

as they get busy with college and careers). One of the great things about exercise is that it's never too

late to start. And don't forget that even small things can count as exercise when you're starting out-like

taking a short bike ride or sweeping fallen leaves. Even walking your dog counts as part of your 60 minutes

a day of exercise (and your vet will tell you that animals need workouts just like humans do, so if your

family dog is fat, he'll benefit from your dedication, too).

1. Why should teens not exercise too much?

A. Because it causes their body to work disorderly.

B. Because it gets them to have an unhealthy weight.

C. Because it will make them become too thin.

D. Because it burns the energy they need to grow up.

2. The underlined part in Para.3 means that _____.

A. you are charged for your exercise

B. you manage how much exercise you need

C. you are greatly addicted to exercising

D. you do some exercise free of charge

3. What is the biggest challenge for people who want to exercise?

A. To find enough time to exercise.

B. To continue to exercise the whole life.

C. To own suitable equipment for exercising.

D. To find a person to exercise together.

4. The subject discussed in Paragraphs 2-3 is that _____.

A. it is not good for you to exercise too much

B. it is helpful to lose weight by exercise

C. it is a good thing to exercise every day

D. it is good for your pet to exercise every day

关于易燃易爆场中作业，下列说法不正确的是（）。

A、易燃、易爆区域的装置均要做设备防静电接地。混凝土地面、橡胶地板等导电性要符合规定

B、对易燃、易爆流体储罐进行测温、采样，不准使用两上或两种以上材质的器具

C、易燃、易爆流体在输送停止后，按规时间静止一定时间，方可进行上罐检尺、测温、采样等作业

D、易产生静电的装置设备必须设静电消除器

砼泵按构造和工作原理可分为（）

A.活塞式

B.挤压式

C.风动式

D.螺旋式

莹光