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问题 选择题

二氧化碳与人们的生产和生活有着广泛的联系，下列关于二氧化碳的认识中，正确的一组是

①在地窖、枯井内二氧化碳含量会比较高

②二氧化碳在水中的溶解量跟压强成反比

③绿色植物光合作用时吸收二氧化碳并放出氧气

④二氧化碳比一氧化碳多一个氧原子[ ]

A.①②

B.③④

C.①③

D.②④

答案

答案：C

单项选择题

在可交换公司债券发行前，( )应当与上市公司股东就预备用于交换的股票签订担保合同。

A．证券登记结算机构

B．公司债券受托管理人

C．债券持有人

D．证券交易所
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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 tile 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 Knicker-bocker 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 modem 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.

The passage implies that until 1869, baseball was played for all of the following reasons EXCEPT ______.

A. exercise



B. leisure
C. profit



D. socializing
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