1、a life preserver in the form of a ring of buoyant material.
圓圈形的有浮力的生命保護者。

2、a life preserver in the form of a ring of buoyant material
圓圈形的有浮力的生命保護者。

3、The life preserver kept him up until the boat came.
救生衣使他保持浮在水面直到小船來救他。