在比例尺为1：1000000的地图上，甲乙两地的图上距离为4厘米，则两地的实际水平距离为[ ]
A、4千米
B、40千米
C、400千米
D、40米
答案：B
地下水源工程主要指什么？
Computer hardware engineers research, design, develop, and test computer hardware and supervise its manufacture and (72) . Hardware refers to computer (73) , circuit boards, computer systems, and related equipment such as keyboards, modems, and printers.
A．fixing
B．building
C．setting
D．installation
