单项选择题
A.the propeller diameter B.the propeller radius C.the pitch angle D.the length of helix
If a line at right angles to the axis rotates about tha...
单项选择题If a line at right angles to the axis rotates about that axis and, at the same time, moves parallel to the axis, it will generate （）.
A.a helix B.a helicoidal C.a curve D.a cone
When a point rotates about an axis and, at the same tim...
单项选择题When a point rotates about an axis and, at the same time, moves parallel to that axis, it describes （）.
A.a line B.a circle C.a helix D.an epllicate
An emergency bilge pumping system is provided and shoul...
单项选择题An emergency bilge pumping system is provided and should be （） of the main bilge pumping system, according to the SOLAS 74 Convention.
A.dependent B.in dependent C.in series D.in parallel
