问题 填空题

小宇打开家中的冰箱门,看到冰箱内的指示灯亮着,而压缩机并没有工作,从而他判断出冰箱内的指示灯和压缩机是        (填“串联”或“并联”)的;当他打开冷冻室的门时,看到侧壁上有很多霜,这是水蒸气        (填物态变化的名称)形成的,当他拿起湿抹布去擦时,抹布却粘在了侧壁上,这是因为抹布上的水        (填物态变化的名称)形成的。

答案

并联  凝华  凝固

题目分析:小宇打开家中的冰箱门,看到冰箱内的指示灯亮着,而压缩机并没有工作,说明它们没在同一电路中互不影响,所以是并联;冷冻室侧壁上的霜是由冰箱内空气中的水蒸气遇冷直接凝华而成的;当他拿起湿抹布去擦时,湿抹布上的水遇冷凝固成冰粘在了侧壁上。

单项选择题
单项选择题

American Museum of Natural History is one of the largest natural and historic museums in the world and one of the main natural history research and education centres in the United States, set up in 1869 and located in the west of the Central Park, Manhattan District, New York. It (1) 7 hectares in its total area, (2) classical types of buildings. The (3) of ancient creatures and humanity is (4) the first place of all the museums in the world, (5) the representative samples from South America, Africa, Europe, Asia and Australia were collected, besides those from the (6) country, the United States.In the museum, there are five kinds of exhibits, including astronomy, mineralogy, human history, and animals in the (7) times and those in modern times. There are thirty-eight exhibition halls with different (8) from 500 to 1,500 square metres. Besides these, there is a Roosevelt Memorial Hall in (9) of President Roosevelt who supported the (10) of the museum, which is also used to have a special exhibition, showing the new important (11) on natural sciences and (12) affairs and social problems, and special topics connected closely with the life of the citizens. Besides this, it is also used for avocation (13) to have all kinds of scientific activities in the laboratories, centres of natural science and centres for citizens. There are more than 10 (14) research departments mainly(15) for collection of samples, research and work of publication.In the museum, there are (16) and sub-libraries of Aulspond ancient amniote, with about 300 thousand books and magazines (17) natural history, many of(18) are very valuable monographs for the first edition. It has published many expert books and magazines, and a large number of propaganda materials, (19) which are the two magazines, Natural History and Members of Museum that have the biggest (20) of their magazines.

2()

A.with

B.of

C.in

D.on