The only objection to be made to it perhaps indeed is that much of the time, it's just more trouble than it's worth to enforce it.

唯一存疑的地方可能是,在大多数时间，实行它太麻烦了。

耶鲁公开课 - 文学理论导论课程节选

And "it" definitely just refers to time and you only use "it" when you're talking about time.

这时，“it” 一词仅指时间，当你在谈论时间的时候，只能使用 “it”。

How long课堂 - SpeakingMax英语口语达人

So basically, the whole society was spending all of the time raising enough food just to support life and there was only 5% left over and that ended up being used in ways like this.

基本上,整个社会全部时间都被用于积累足量食物,这仅是为了维持生计,只剩下5%的时间,被用来建造金字塔,为法老服务

耶鲁公开课 - 关于食物的心理学、生物学和政治学课程节选