life expectancy
noun [ C usually singular or U ] uk/ˈlaɪf ɪkˌspek.tən.si/ us/ˈlaɪf ɪkˌspek.tən.si/
（尤指人的）预期寿命
the length of time that a living thing, especially a human being, is likely to live
Life expectancy in Europe increased greatly in the 20th century. 欧洲人的预期寿命在20世纪大幅增长。