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【单选题】
减压阀一般串联装设于气动系统的路口,或需要调压的支路路口。那么,减压阀调节的是进口压力还是出口压力?A.
进口压力
B.
出口压力
C.
流速
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参考解析：
知识点：
皮皮学刷刷变学霸
举一反三
【单选题】下列各种说法中正确的是
A.
乙烯和甲苯都能使酸性高锰酸钾溶液褪色
B.
凡是能起银镜反应的物质一定是醛
C.
在酯化反应中，羧酸脱去羧基中的氢原子，醇脱去羟基生成水和酯
D.
苯酚有弱酸性，俗称石炭酸，因此它是一种羧酸
【单选题】In what kind of conditions are the great old houses and castles nowadays?
A.
They are under the threat of modern technology.
B.
Less and less support is got for their repair and maintenance.
C.
Heavy taxation and estate duty caused their being desertion.
D.
They are more dynamic, vigorous and valuable than before.
【单选题】In what kind of conditions are the great old houses and castles nowadays?
A.
They are under the threat of modern technology.
B.
Less and less support is got for their repair and maintenance.
C.
Heavy taxation and estate duty caused their being deserted.
D.
They are more dynamic, vigorous and valuable than before.
【判断题】3~76.步进电动机的选用应注意:根据系统的特点选用步进电动机的类型、转矩足够大以便带动负载、合适的步距角、合适的精度、根据编程的需要选择脉冲信号的频率。
A.
正确
B.
错误
【简答题】SECTION A COMPOSITION (35 MIN) It is a popular phenomenon that nowadays some houses in China are labeled with foreign names and some traditional Chinese houses are demolished for the new foreign ones....
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