zài / jīng / jì / xué / kè / shàng / lǎo / shī / jiǎng / jiě / le / bì / yào / chǎn / pǐn / hé / shèng / yú / chǎn / pǐn / de / qū / bié

在经济学课上，老师讲解了必要产品和剩余产品的区别。

In economics class, the teacher explained the difference between necessary products and surplus products.