阴阳之“征兆”是A．内与外 B．明与暗 C．上与下 D．水与火

城市广播系统，有( )两种方式。

A．无线电广播和有线广播

B．中波和短波

C．中短波和调频

D．地方广播和国际广播

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.

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

A．exercise

B．leisure

C．profit

D．socializing

如果计息周期无限期缩短，并按复利计息，称为连续复利。( )

中国四大名楼是什么？

领导者的权威是（）的结果

A.依靠强制力

B.拉拢下属

C.恰当运用权力

D.收买人心