气流组织的基本布置原则正确的是（）
A. 排风口应尽量靠近有害物源或有害物浓度高的区域，把有害物迅速从室内排出
B. 送风口应尽量接近操作地点。送入通风房间的清洁空气，要先经过操作地点，再经污染区域排至室外
C. 在整个通风房间内，尽量使送风气流均匀分布，减少涡流，避免有害物在局部
D. 地区的聚集
E. D．在浓度高的房间中应该分散排放
在Proteus中提供的虚拟仪器主要有（）
A. OSCILLOSCOPE（示波器）
B. LOGIC ANALYSER（逻辑分析仪）
COUNTER TIMER（计数/定时器）
D. VIRTUAL TERMINAL （虚拟终端）
E. SPI DEBUGGER（SPI总线调试器）
F. SIGNAL GENERATOR（信号发生器）
G. DC VOLTMETER（直流电压表）和 DC AMMETER（直流电流表）
H. AC VOLTMETER（交流电压表）和 AC AMMETER（交流电流表）
Which of the following best explains why market prices are useful to a financial manager when performing a cost-benefit analysis（）
A. They can be used to determine how much an asset can be sold for
B. They can be used to convert different services and commodities into equivalent cash values which can be compared
C. They allow all commodities and services to be assigned a fixed and unchanging value
D. They can be evaluated to determine whether the market in which the manager exchanges goods and services offers true value
What is the bid-ask spread（）
A. the difference in price available for an immediate sale of a stock and the immediate purchase of the stock
B. all of the costs and fees that a stock exchange charges in order to process a transaction
C. the rise or fall in the value of a stock between the time it is acquired by an investor and sold by that investor
D. the difference in the selling price of a stock between different exchanges
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