We should not start the engine unless turning gear is __________.
A. on
B. disengaged
C. bolted
D. unscrewed
查看答案
Before “standby” is rung on the engine telegraph, it is usual to give the main engine __________ ahead and astern.
A. a brief trial with turning gear
B. a brief trial on power
C. a long trial by steering gear
D. a long trial on air
回归年等于()朔望月的长度
A. 11
B. 12
C. 12.3683
D. 13.3683
回归年和朔望月的平均长度分别为()
A. 365.2422天, 29.5306天
B. 365.2425天, 29.5603天
C. 365.2425天, 29.5036天
D. 365.2422天, 29.5036天
历法中历年的制定主要参考()
A. 恒星年
B. 回归年
C. 食年
D. 近点年
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