问题 填空题

如图是某家庭电路的一部分,其中a、b为火线或零线,甲、乙两处分别装有电灯或开关,则_______(选填“甲”或“乙”)处应该安装开关。如果还想在这个电路中安装冰箱插座,那么冰箱插座应该和已有的电灯___________(选填“串联”或“并联”)。

 

答案

_______    ____并联

分析:(1)家庭电路中,为了安全,保险丝要接在火线上,开关也应接在火线上;

(2)家庭电路中,各用电器之间是并联的,同时使用的用电器越多,干路中的电流越大,保险丝就越容易熔断.

解答:解:为了安全,保险丝应接在火线上,而不是零线上,甲处应该安装开关;

家庭电路中,各用电器之间是并联的,同时使用的用电器越多,干路中的电流越大,保险丝就越容易熔断

故答案应填:甲 并联

阅读理解

阅读理解。

     My bookshelves are full of dust-and with good reason. When it comes to cleaning that part of my home,

I suffer from the most serious case of avoidance (回避反应症).

     The thing is this: when I do set out to clean and re-organize my books, which seldom happens, I place

myself into a really bad situation. No sooner do I take a title from the shelf, blow off the dust, and wipe down

the cover than I find myself sitting on the floor with legs crossed and my back against the wall. Pretty soon

books get piled up on my legs as I am reunited with old friends.

     It is as if these books have voices, and each wants to say its piece. "Remember me? I was given to you

when you went into the Navy, so that you would never lack for companionship," one whispers. Another says,

"I was your first book of poems, given to you before you learned to love poetry." And a third, "I was the book

that made history so attractive to you."

     Perhaps the greatest pleasure of re-organizing my books are the surprises-or better said, reunions-that

occur. During my latest book-cleaning adventure, I found one that had fallen behind the shelf:"Tales of Edgar

Allan Poe." Not an unusual title, but the words written on the first page made it very special:"With Love from

Mom and Dad, Christmas 1965." What's this? A book on the physics of lasers (激光). It is filled with

mathematical statements, and I had bought it at a library sale when I was 12, not long after the laser had been

invented. I couldn't understand a bit of it, but I did learn what "laser" meant.

     What I end up with when I empty my bookshelves is a cross-section (横剖面) of my personal history. It's

like a road cut where one sees all the layers of rock going back through time to the beginning of the simplest

life forms. The books I've read-and kept-are not just old friends. They are my résumé.

1. What could be said about the author?

A. He is too busy to tidy up his bookshelves.

B. He considers his books treasured possessions.

C. He has made a lot of notes in his books.

D. He is a lover of science books.

2. By saying that his books have voices, the author means _____.

A. they bring back happy memories

B. they are recorded in human voice

C. they say a lot about human history

D. they offer good topics for discussion

3. What does the author enjoy most from re-organizing his books?

A. Finding some missing books.

B. Putting books in good order.

C. Learning something new from the books.

D. Rediscovering interesting stories behind some books.

4. The underlined word "résumé" in the last paragraph probably means _____.

A. personal history

B. precious notes

C. good companion

D. simple life forms

单项选择题