系统实施阶段主要文档之一是
A．可行性报告
B．系统分析说明书
C．系统设计报告
D．用户手册
参考答案：D
The waterfall can be seen _ __. Its sound may be heard __ two miles. It looks even more beautiful____.
A．at a distance; in a distance of ; from a distance
B．from a distance; in the distance of; at a distance
C．in the distance; from a distance; at a distance
D．in the distance; at a distance of; from a distance
下列属于Java关键词的是( )。
A．TRUE
B．goto
C．float
D．NULL
