life·line /ˈlaɪfˌlaɪn/
 救生索,生命線


 lifeline
      n 1: a crease on the palm; its length is said by palmists to
           indicate how long you will live [syn: line of life, {life
           line]
      2: support that enables people to survive or to continue doing
         something (often by providing an essential connection);
         "the airlift provided a lifeline for Berlin"; "she offered
         me a lifeline in my time of grief"
      3: line that raises or lowers a deep-sea diver
      4: line thrown from a vessel that people can cling to in order
         to save themselves from drowning