bottomryn.船舶抵押契约；冒险贷借bottomn.底部；底端adj.底部的v.触底；打(基础)bottom keel angle主龙骨底角材bottom topography水底地形bottom tow method底拖法bottom gravimeter海底重力仪bottom pinch roll下夹送辊bottom reflection海底反射bottom sea waters近底层海水bottomry contract船舶抵押合同bottom trash rack底部拦污栅Bottom Literature底层写作