单项选择题
A.lower than
B.higher than
C.below
D.equal to
单项选择题 Large pipes or () are fitted between the steam and water drums to ensure good natural circulation of water.
单项选择题 () system is arranged to ensure that water can be drawn from any tank or the sea and discharged to any other tank or the sea as required to trim the vessel.
单项选择题 () connected to the moving tiller will bring the floating lever pivot and the lever into line at right angles to the screw shaft axis.