问题 选择题

关于家庭电路,下列说法中正确的是(     )

A.应将控制用电器的开关接在火线上

B.螺丝口灯座的螺旋套,只准接在零线上

C.熔丝熔断一定是电路中某处发生短路

D.有金属外壳的家用电器,其插座应安装接地线

答案

ABD

题目分析:A、当开关断开时,为了使用电器不带电,所以开关应该与火线相连,所以A选项正确;

B、因为灯座的螺旋套很容易被人接触到,所以从安全的角度考虑应该接在零线上,所以B正确;

C、熔断丝的作用是当电路中电流过大时,熔断丝会被烧,电流过大的原因可能是短路,也可能是电路的总功率过大,所以C选项错误;

D、当金属外壳的用电器内部线路破损与外壳接触时,外壳会带电,如果将外壳与大地相连,人接触时也是安全的,否则人会触电,所以有金属外壳的家用电器,其插座应安装接地线,所以D选项正确;

所以选A、D.

点评:根据家庭电路的正确连接进行分析,各元件的连接都应该从安全方面考虑.

阅读理解

One of the greatest contributors to the first Oxford English Dictionary was also one of its most unusual. In 1879, Oxford University in England asked Prof. James Murray to serve as editor for what was to be the most ambitious dictionary in the history of the English language. It would include every English word possible and would give not only the definition but also the history of the word and quotations(引文) showing how it was used.

This was a huge task, so Murray had to find volunteers from Britain, the United States, and the British colonies to search every newspaper, magazine, and book ever written in English. Hundreds of volunteers responded, including William Chester Minor. Dr. Minor was an American surgeon who had served in the Civil War and was now living in England. He gave his address as “Broadmoor, Crowthorne, Berkshire,” 50 miles from Oxford.

Minor joined the army of volunteers sending words and quotations to Murray. Over the next 17 years, he became one of the staff’s most valued contributors.

But he was also a mystery. In spite of many invitations, he would always decline to visit Oxford. So in 1897, Murray finally decided to travel to Crowthorne himself. When he arrived, he found Minor locked in a book-lined cell at the Broadmoor Asylum(精神病院) for the Criminally Insane.

Murray and Minor became friends, sharing their love of words. Minor continued contributing to the dictionary, sending in more than 10,000 submissions in 20 years. Murray continued to visit Minor regularly, sometimes taking walks with him around the asylum grounds.

In 1910, Minor left Broadmoor for an asylum in his native America. Murray was at the port to wave goodbye to his remarkable friend.

Minor died in 1920, seven years before the first edition of the Oxford English Dictionary was completed. The 12 volunteers defined 414,825 words, and thousands of them were contributions from a very scholarly and devoted asylum patient.

小题1:According to the text, the first Oxford English Dictionary ____.

A.came out before Minor died

B.was edited by an American volunteer

C.included the English words invented by Murray

D.was intended to be the most ambitious English dictionary小题2:How did Dr. Minor contribute to the dictionary?

A.He helped Murray to find hundreds of volunteers.

B.He sent newspapers, magazines and books to Murray.

C.He provided a great number of words and quotations.

D.He went to England to work with Murray.小题3:Which of the following best describes Dr. Minor?

A.Brave and determined.

B.Cautious and friendly.

C.Considerate and optimistic.

D.Unusual and scholarly.小题4:What does the text mainly talk about?

A.The history of the English language.

B.The friendship between Murray and Minor.

C.Minor and the first Oxford English Dictionary.

D.Broadmoor Asylum and its patients.

单项选择题