遇到一个长句,其中that在句中承担什么成分,起到什么作用,是否指代什么,搞不清楚,ThosewhowatchedTVforlessthan7hoursadaywerealso50percentmorelikelytodevelopmemorylossthanthosewhospentlongerthanthat

Question

遇到一个长句,其中that在句中承担什么成分,起到什么作用,是否指代什么,搞不清楚,
Those who watched TV for less than 7 hours a day were also 50 percent more likely to develop memory loss than those who spent longer than that staring at the screen.请问句中that如何理解?

Answer 1

that是代词,指的是7 hours a day.
这里比较的两方是：Those who watched TV for less than 7 hours a day,those who spent longer than that.每天看电视少于7小时的人,和花时间比它（每天7小时）多的人.