【单选题】Ice-breaker assistance for convoy will start at 1930 UTC.
A.
Ice-breaker assistance for fleet passage started at 1930 UTC.
B.
Ice-breaker assistance for fleet passage is due to start at 1930 UTC.
C.
Ice-breaker assistance for M.V. Convoy started at 1930 UTC.
D.
Ice-breaker assistance for M.V. Convoy is due to start at 1930 UTC.
【单选题】040mol/L碳酸溶液的PH值为()。(Ka1=4.2×10-7,Ka2=5.6×10-11)
【单选题】Refseq数据库中,NM符号代表的是那种序列信息?
【简答题】有一批半径为 1cm 的球 , 为了提高球面的光洁度 , 要镀上一层铜 , 厚度定为 0 . 01cm . 估计一了每只球需用铜多少 g ( 铜的密度是 8. 9g/cm 3 )?
【单选题】Ice-breaker assistance for convoy will start at 1930UTC
A.
Ice-breaker assistance for fleet passage stared at 1930UTC
B.
Ice-breaker assistance for fleet passage is due to start at 1930UTC
C.
Ice-breaker assistance for M.V. Convoy started at 1930UTC
D.
Ice-breaker assistance for M.V. Convoy is due to start at 1930UTC
【单选题】A circuit breaker differs from a fuse in that a circuit breaker ().
A.
melts and must be replaced
B.
is enclosed in a tube of insulating material with metal ferrules at each end
C.
gives no visual indication of having opened the circuit
D.
trips to break the circuit and may be reset
【单选题】A breaker's cheque is a negotiable instrument.
【单选题】A circuit breaker differs from a fuse in that a circuit breaker ______.
A.
melts and must be replaced
B.
is enclosed in a tube of insulating material with metal ferrules(环) at each end
C.
gives no visual indication of having opened the circuit
D.
trips to break the circuit and may be reset
【单选题】The purpose of a main switchboard circuit breaker's reverse power trip is to _____.
A.
prevent main circuit overload
B.
protect the circuit breaker blowout coil
C.
prevent alternator motorization
D.
prevent low voltage tripout