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【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.
if the engine moves too fast
B.
if the engine’s amplitude increases
C.
if a tire gets out of balance
D.
if damage occurs in the 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.
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
【单选题】下述各项原木构件的相关设计要求中，哪几项与规范相符( )Ⅰ．验算挠弯和稳定时，可取构件的中央截面；Ⅱ．验算抗弯强度时，可取最大弯矩处的截面；Ⅲ．标注原木直径时，以小头为准；Ⅳ．标注原木直径时，以大头为准。
A.
Ⅰ、Ⅱ
B.
Ⅰ、Ⅱ、Ⅲ
C.
Ⅱ、Ⅲ
D.
Ⅰ、Ⅱ、Ⅳ