translation.en: Just suppose, as I said, that we do acquire -- let's say we do it today for the sake of argument -- the ability to confer 30 extra years of healthy life on people who are already in middle age, let's say 55.
translation.zh: 我们假设，如果正如我所说的， 我们 - 假设说今天 – 就拥有能够给现在已是中年，假设说五十五岁的人，