问题 选择题

在卫生间里洗过澡后,室内的玻璃变得模糊不清,过了一段时间,镜面又变得清晰起来,镜面上发生的这两种现象的物态变化是(       )

A.先液化,后汽化

B.先汽化,后液化

C.只有液化

D.只有汽化

答案

答案:A

题目分析:液化是指气体变为液体的现象;汽化是指液体变为气体的现象;液化和汽化是两个相反的过程,汽化吸热,液化放热.洗澡的时候,水大量蒸发,有许多水蒸气遇到冷的镜子液化形成小水滴,过了一段时间后,小水滴又蒸发变为水蒸气,所以又变得清晰起来.故选A.

点评:解决本题的关键是对生活中的物态变化的了解和掌握,体现了由物理走向生活的理念.

填空题

Part 4


Questions 26-45


·Read the following text and decide which answer bestfits each space.
·For questions 26-45, mark one letter A, B, C or D on the Answer Sheet.

Newspapers


Who won the World Cup 1994 football game What happened at the United Nations How did the critics like the new play When an event takes place, newspapers are on the streets (26) the details. (27) anything happens in the world, reporters are on the spot to (28) the news.
Newspapers have one basic (29) to get the news as quickly as possible from its source, from those who make it to those who want to (30) it. Radio, telegraph, television, and (31) inventions brought competition for newspapers. So did the development of magazines and other means of communication. (32) this competition merely spurred the newspapers on. They quickly made (33) of the newer and faster means of communication to improve the speed and (34) the efficiency of their own operations. Today more newspapers are printed and read than ever before.
Competition also led-newspapers to branch out into many other fields. Besides keeping readers (35) of the latest news, today’s newspapers (36) readers about politics and other important and serious matters. Newspapers influence readers’ economic choices (37) advertising. Most newspapers depend on advertising for their very (38) Newspapers are sold at a price that (39) to cover even a small fraction of the cost of production. The main (40) of income for most newspapers is commercial advertising. The (41) in selling advertising depends on a newspaper’s value to advertisers. This is measured (42) circulation. How many people read the newspaper Circulation depends (43) on the work of the circulation department and on the services or entertainment (44) in a newspaper’s pages. But for the most part, circulation depends on a newspaper’s value to readers as a source of information (45) the community, city, country, state, nation, and world—and even outer space.

A.by

B.via

C.at

D.about

单项选择题