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【单选题】
PLC的扫描周期不包括( )A.
输入采样阶段
B.
定时扫描阶段
C.
输出刷新阶段
D.
程序执行阶段
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举一反三
【简答题】The researchers have conducted an experiment to prove that people will act in emergencies when ______ A) they are in pairs B) they are in groups C) they are alone D) they are with their friends
【单选题】The researchers have conducted an experiment to prove that people will act in emergencies when______.
A.
they are in pairs
B.
they are in groups
C.
they are alone
D.
they are with their friends
【单选题】Researchers have known for years that animals have a 'clock' somewhere in their brains a control-centre that regulates circadian(生物节奏的) rhythms. Circadian rhythms are the body's daily biological cycle...
A.
Right
B.
Wrong
C.
Not mentioned
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