单项选择题 系统总线中，地址线的功能是（     ） A. 选择主存储器单元地址  B. 选择进行信息传输的设备 C. 选择外存地址 D. 指定主存和I/O设备接口电路的地址

单项选择题 An accountant is paid $30,000 per annum and spends 2 weeks working on appraising project Alpha. Why should the accountant NOT charge half of his month's salary to the project? A. Because his salary cannot be apportioned  B.  Because his salary is not incremental C. Because his salary is not a cash flow D. Because his salary is an opportunity cost

单项选择题 发酵过程中会产太多的泡沫给反应带来不利的影响，下列不是采用化学消泡的消泡机理是 A、降低气泡表面张力 B、降低压力促使破裂 C、降低液膜的弹性 D、降低膜表面的黏度