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【简答题】
编写一个初始化程序，使8255A的PC 7 端输出一个负跳变。如果要求从PC 5 端输入一个负脉冲，则初始化程序应该进行哪些修改?
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皮皮学刷刷变学霸
举一反三
【单选题】This passage uses all of the following words to talk about the symbolic significance of sports and sports movies EXCEPT ______.
A.
arena
B.
metaphor
C.
simile
D.
vehicle
【单选题】The author uses all of the following expressions interchangeably to support his view EXCEPT ______.
A.
literature processor.
B.
message transference.
C.
meaning conveyor.
D.
chaotic subjectivism.
【单选题】All of the following are mentioned in the passage as reasons for allowing unlabeled uses of drugs EXCEPT ______.
A.
the increased cost to the patient of buying an FDA-approved drug
B.
the medical benefits which can accrue to the patient through unlabeled use
C.
the time lag between initial discovery of a medical use and FDA approval of that use
D.
the possibility that a medically beneficial use may never be clinically documented
【单选题】下列说法正确的是（ ）
A.
有一个角是60°的等腰三角形是等边三角形
B.
有一个角是45°的等腰三角形是等腰直角三角形
C.
等腰三角形的对称轴是顶角平分线
D.
直角三角形一边上的中线等于这条边的一半
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