问题 单项选择题

在一般情况下,动力和照明宜共用变压器,属于下列( )情况之一时,可设专用变压器。

A.照明负荷较大,或动力和照明共用变压器由于负荷变动引起的电压闪变或电压升高,严重影响照明质量及灯泡寿命时,可设照明专用变压器
B.单台单相负荷很大时,可设单相变压器
C.冲击性负荷(试验设备、电焊机群及大型电焊设备等)较大,严重影响电能质量时,可设专用变压器
D.在TT系统的低压电网中,照明负荷应设专用变压器

答案

参考答案:A,B,C

解析: 《工业与民用配电设计手册》第3版P41。

完形填空

阅读表达(共5小题:每小题2分,满分10分)

阅读下面的短文,并根据短文后面的要求答题。(请注意问题后的字数要求)

Studies and reports seem to come in everyday talking about the state of the world. Global warming and pollution are threatening the delicate balance of life on Earth. The vast amount of troubles in the world can make anything we do seem unmeaning. But if we can do just a few things to help, the joined efforts can create a huge difference in both the world and in our lives. If you are not sure where to begin here are some simple things that can create a big change.

Grow your own garden. Growing your own garden can create a tremendous difference. Having fresh fruits and vegetables at your finger tips can not only improve your health, it can also save you money. Spending time each day working in your garden is wonderful exercise and a great way to get plenty of sunshine.

Stop buying chemical cleaners. The special chemicals to clean their house can have bad effect on your health and the environment. Instead of buying more bottles of chemicals and creating more waste,try some of the simple cleaner ideas that you can make yourself. Vinegar and baking soda is one of the simplest, most effective, and cheapest cleaning solutions available. Lemon juice is another safe and effective cleaner that can remove soap scum and whiten clothes as well as many other uses.

Change your light bulbs. Replacing your ordinary light bulbs with low energy bulbs can both  _____________ and help the environment. These long lasting bulbs reduce your energy bill and do not need to be replaced as often as conventional bulbs.

Recycle. The tried and true method of helping the environment is recycling. Most cities have recycling centers or recycling pick-up available for people. Plastic, glass, paper, even old phonebooks can be recycled and used for other things.

1. List three appropriate measures you can do to help the environment. (Please answer within 10 words.) 

(1) _____________   (2)_____________  (3)___________

2. What is the best title of this passage ? (Please answer within 10 words)

_____________________________________________________________________

3. Fill in the blank in Paragraph 4 with proper words. (Please answer within 6 words.)

_____________________________________________________________________

4. Which sentence in the text is the closest in meaning to the following one?

Don’t buy bottles of chemical and don’t make much waste any longer, you can use some simple ways to clean.

____________________________________________________________________

5. Translate the underlined sentence in Paragraph 2 into Chinese.

____________________________________________________________________

单项选择题