How does an icebreaker normally free a ship which has become beset while navigating independently?()
A. By backing down the track and cutting out ice on either bow
By approaching from the stern and crossing ahead at an angle of 20°to 30°to the beset ship's course
C. By overtaking the beset ship,running ahead and then backing down the track to the beset vessel
D. By approaching the vessel from astern and towing the beset vessel stern first
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在加法模型中,当季节变动成分S或循环变动成分C不存在时,通常S或C取值为1。
A. 正确
B. 错误
空气中CO含量0.05mg/L时,可连续工作一小时,而每次工作间隔时间不少于2小时。
A. 正确
B. 错误
计算元月1日测定I的放射性浓度为20mci/ml,元月16日要取用5mci,应该取多少体积?
按照汇款方式划分,行内客户汇款分为()。
A. 2小时到账
B. 实时汇款
C. 证券类汇款