某学生将一氯丙烷和NaOH溶液共热煮沸几分钟后,冷却,滴入AgNO3溶液,结果未

题型:选择题

问题:

某学生将一氯丙烷和NaOH溶液共热煮沸几分钟后,冷却,滴入AgNO3溶液,结果未见到白色沉淀生成,其主要原因是(  )

A.加热时间太短

B.不应冷却后再滴入AgNO3溶液

C.加AgNO3溶液后未加稀HNO3

D.加AgNO3溶液前未用稀HNO3酸化

考点:物质的鉴别
题型:选择题

进入青春期,我们对异性产生好感。下列做法正确的是[     ]

A、在异性同学面前感到害羞,回避与异性交往

B、排斥与异性同学的交往

C、有意疏远异性同学,觉得与异性同学交往对自己不利

D、以正确的态度对待异性交往,并自然、大方地与异性交往

题型:选择题

---Thank you for giving us a fantastic party!   ---_________.

A.I’m happy you all enjoy it.

B.Please don’t say so

C.Come here next time.

D.I didn’t cook so well.

题型:选择题

某盐的混合物中含有0.2mol Na+、0.4mol Mg2+、0.4mol Cl-,则SO42-为(  )

A.0.1mol

B.0.3mol

C.0.5mol

D.0.15mol

题型:选择题

( )城市的城市规划被称为第一份城市范围的总体规划。

A.巴黎

B.伦敦

C.纽约

D.芝加哥

题型: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.

4()

A.in

B.of

C.by

D.at

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