长度在（）以上的采煤工作面叫长壁式采煤法。A、30m， B、40m， C、50m，

As a result of the serious flood, twothirds of the buildings in the area ________. [ ]

A. need repairing  

B. needs to repair

C. needs repairing  

D. need to repair

-羟丁酸脱氢酶检测，主要是反应下列乳酸脱氢酶同功酶中哪一种的活性

A．LD1

B．LD2

C．LD3

D．LD4

E．LD5

现券市场做市商开盘30分钟内，必须发送哪些债券类型的做市报价？（）

A、新发关键期限国债

B、政府债券

C、政府类开发金融机构债券

D、非政府信用债券

对于一个大型的软件项目，由于项目的复杂性，需要进行一系列的估算处理。主要按 (9) 和 (10) 手段进行。估算的方法分为3类：从项目的整体出发，进行 (10) 的方法称为 (11) 估算法。把待开发的软件细分，直到每一个子任务都已经明确所需要的开发工作量，然后把它们加起来，得到软件开发总工作量的方法称为 (12) 估算法。而把待开发的软件项目与过去已完成的软件项目做类比，区分出类似部分和不同部分分别处理的方法称为 (13) 估算法。

（12）处填（）。

A．差别

B．自顶向下

C．自底向上

D．专家判定技术

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