都是表示量，大量少量，quantity后面➕可数和不可数都行，amount后面只➕不可数名词。

至于后面用的是单V还是复V，

1. 首先看quantity和amount，它们是复数就➕复V，不管后面修饰的名词可数还是不可数。
2. a+它们的形式，quantity修饰不可数就➕单V，修饰可数复就➕复V。amount都是➕单V。
3. the +它们的形式，都加单V

A large quantity of bananas were on sale.

A large quantity of beer was sold.

Quantities of nuts were on the table.

Large quantities of wheat are being sent abroad.

The quantity of books in the library is amazing.

The quantity of heat in the office has not been increased.