你可能感興趣的試題

Mooring lines should be turned end-for-end occasionally. This is because（）.

A.a line is weakened by constantly pulling on it in one direction
B.normal wear on the line is thus distributed to different areas
C.it prevents the line from kinking or unlaying
D.it prevents permanent misalignment of the line's internal strands

單項(xiàng)選擇題

Most propellers on merchant vessels are constructed of（）.

A.managanese bronze
B.cast iron
C.mild steel
D.improved plow steel