主语:Many people over 65
谓语:are left 是被动语态
主补:sounding much older than they are.是现在分词短语作主补.
此句若还原成主动语态则为:
(voice) leaves many people over 65 sounding much older than they are.
在主动语态中,sounding much older than they are现在分词短语做宾语补足语.
变成被动语态后,就成了主语补足语.
sound和many people over 65在逻辑关系上为主动形式,故用现在分词sounding .
句意:很多65岁以上的老人听起来要比实际年龄老.