电子教案是将传统教案中的内容转变成计算机能处理的数字信息格式后储存于记录介质（磁盘、光盘）中的现代教案，由文字、图片、图像、图表、声音、动画、视频等多种媒体信息组成，下面关于电子教案的功能特征描述正确的选项是（）。
A.电子教案有利于教案的修订和保存
B.电子教案便于携带和学术交流
C.电子教案可实现超文本组织信息，利于非线性知识的安排
D.电子教案可以使抽象的教学内容具体化
参考答案：A, B, C, D
| 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 tone of the passage is ______.
A．persuasive
B．informative
C．biased
D．argumentative