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问题 填空题

某兴趣小组为了检验在氢气和二氧化碳的混合气体中是否混有一氧化碳，用下图所示装置进行实验。试回答：

（1）装置B中盛放的试剂是___________，目的是为了_____________________________；

（2）当观察到_______________________________时，说明混合气体中一定混有一氧化碳。

答案

（1）澄清石灰水，检验二氧化碳是否已除尽
（2）D中石灰水浑浊而B中石灰水澄清

（1）检验一氧化碳通常是让它先生成二氧化碳，然后再用澄清石灰水去检验二氧化碳．所以要先除去原有二氧化碳的干扰，AB装置的目的就是除去二氧化碳；

（2）根据二氧化碳的性质和装置的特点推测现象；

单项选择题

There has been much speculation about the origin of baseball. In 1907 a special commission decided that the modern game was invented by Abner Doubleday in 1839. One hundred years later the National Baseball Museum was opened to honor Doubleday. Historians, however, disagree about the origin of baseball. Some say that baseball comes from bat-and-ball games of ancient times. It is a matter of record that in the 1700s English boys played a game they called "baseball". Americans have played a kind of baseball since about 1800. At first the American game had different rules and different names in various parts of the country — "town ball", "rounders", or "one old cat". Youngsters today still play some of these simplified forms of the game.Baseball did not receive a standard set of rules until 1845, when Alexander Cartwright organized the Knickerbocker Baseball Club of New York City. The rules Cartwright set up for his nine-player team were widely adopted by other clubs and formed the basis of modern baseball. The game was played on a "diamond" infield with the bases 90 feet apart. The first team to score 21 runs was declared the winner. By 1858 the National Association of Baseball Players was formed with 25 amateur teams. The Cincinnati Red Stockings began to pay players in 1869.

What was the first professional baseball team called

A．New York Knickerbockers.

B．Milwaukee Braves.

C．Cincinnati Red Stockings.

D．Brooklyn Dodgers.
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单项选择题

自基金终止之日起（）个工作日内成立清算小组。

A.3

B.5

C.7

D.15
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