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参考答案：
参考解析：
刷刷题刷刷变学霸
举一反三
【多选题】Q345和Q245钢法兰在下列任一情况下应经正火热处理：（）
A.
法兰断面厚度大于50mm
B.
法兰断面厚度大于60mm
C.
锻制法兰
D.
带颈法兰（热轧或锻制）
【单选题】Questions 62 to 66 are based on the following passage. If a mother pushes her small son in a swing (秋千), giving only a light force each time he returns, eventually he will be swingirg.quite high. The ...
A.
the speed of a motor in revolutions
B.
the frequency at which a motor vibrates
C.
the amplitude of an engine that oscillates
D.
the changes in a dial within a ear engine
【单选题】Questions 62 to 66 are based on the following passage. If a mother pushes her small son in a swing (秋千), giving only a light force each time he returns, eventually he will be swingirg.quite high. The ...
A.
vibrate
B.
resonate
C.
swing
D.
oscillate