Care must be taken to condition the （）in the boiler to prevent scaling, and corrosion, which can weaken the pressure vessel. water。 fuel。 steam。 air。
A vessel proceeding along the course of a narrow channel shall keep as near to the outer limitof the channel which lies on her starboard side as it is safe and practicable.Which one of the followings does the statement express?（）. A vessel shall proceed near the other vessel on her starboard side on the narrow channel since it is safe and practicable。 A vessel shall avoid proceeding near the starboard outer limit of a narrow channel as long as it is safe and practicable。 A vessel shall avoid proceeding along the channel because it is not safe and practicable。 A vessel shall proceed near the starboard outer limit of a narrow channel to the degree in which it is safe and practicable。
申请考核单位应当在《计量标准考核证书》有效期届满六个月前向主持考核的计量行政部门提出计量标准的复查考核申请。（）
船舶在码头装卸货期间发生火灾，火势较大时，如认为可以自救，就不必向岸方消防队报警。
船舶发生大范围火灾后，发现者的行动首先是立即灭火。
测量方法是指测量是（）。
