✔ 最佳答案
a.) To the lender, interest is the compensation for postponed consumption.
To the borrower, interest is the price of earlier availability.
b.) interest 係future increase in Job salary 定係 postponed leisure time ？
interest 係 future increase in Job salary
因為interest 是一樣額外多出黎的新野
例如你借本書比人，人地還書果陣比個書籤你，書籤對你黎講是一樣額外多出黎的新野，所以是interest （compensation for postponed consumption）
但係，postponed leisure time 並冇新的野彈出黎，對於你黎講，你冇任何得/失，
因為study 完之後你可以繼續 leisure time ，你並冇失去
所以 interest 係 future increase in Job salary
（講開都講埋，呢題的interest 除左係 future increase in Job salary 之外，仲有好多答案，例如將來更高薪的職業等等，將來更高薪的職業係postponed leisure time 之後爆出黎的新野，都係interest ）
