指令周期是________。
A. CPU执行一条指令的时间
B. CPU从主存取出一条指令的时间
CPU从主存取出一条指令加上执行这条指令的时间
Which of the following provides the hard evidence that Mars was once a wet planet？
A. Schiaparelli
B. spacecraft
C. photographs shot from orbit
D. Martian rover Opportunity
"Outlays" in the seventh paragraph is closest in meaning to ______.
A. taxes
B. money
C. incentives
D. tax increases
存款创造和收缩过程的原理相同，只是方向相反。()
A. 正确
B. 错误
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