单项选择题
A.to windward should be opened and the ones to leeward should be closed B.to leeward should be opened and the ones to windward should be closed C.should be opened D.should be closed
Cracks may be prevented from developing at the corners ...
单项选择题Cracks may be prevented from developing at the corners of welded plating inserts by（）.
A.squaring the corners B.rounding the corners C.plug welding the corners D.slot welding the corners
Connecting elements of a mooring system should be fabri...
单项选择题Connecting elements of a mooring system should be fabricated from（）.
A.cast iron B.forged steel C.stainless steel D.cast steel
Chain slings are suitable for heavy slender articles，su...
单项选择题Chain slings are suitable for heavy slender articles，such as（）.
A.timber or steel rails B.locomotives or boilers C.railway passenger coaches D.motor vehicles
