问题 选择题

用向上排空气法收集氧气时,验满的方法是 [ ]

A.看集气瓶周围是否有气泡冒出     

B.用带火星的木条伸入集气瓶中,看是否复燃

C.用燃烧的木条伸入集气瓶中,看燃烧是否更旺

D.用带火星的木条放在集气瓶口,看是否复燃

答案

答案:D

单项选择题 案例分析题
单项选择题

Who won the World Cup 1994 football game What happened at the United Nations How did the critics like the new play (1) an event takes place, newspapers are on the streets (2) the details. Wherever anything happens in the world, reporters are on the spot to (3) the news.

Newspapers have one basic (4) , to get the news as quickly as possible from its source, from those who make it to those who want to (5) it.

Radio, telegraph, television, and (6) inventions brought competition for newspaper. So did the development of magazines and other means of communication. (7) , this competition merely spurred the newspapers on. They quickly made use of the newer and faster means of communication to improve the (8) and thus the efficiency of their own operations. Today more newspapers are (9) and read than ever before. Competition also led newspapers to branch out into many other fields. Besides keeping readers (10) of the latest news, today’s newspapers (11) and influence readers about politics and other important and serious matters. Newspapers influence readers’ economic choices (12) advertising. Most newspapers depend on advertising for very (13) .

Newspapers are sold at a price that (14) even a small fraction of the cost of production. The main (15) of income for most newspapers is commercial advertising. The (16) in selling advertising depends on a newspaper’s value to advertisers. This (17) in terms of circulation. How many people read the newspaper

Circulation depends (18) on the work of the circulation department and on the services or entertainment (19) in a newspaper’s pages. But for the most part, circulation depends on a newspaper’s value to readers as a source of information (20) the community, city, county, state, nation, and world—and even outer space.

3()

A.gather

B.spread

C.carry

D.bring