苹果的数量是5个用英语怎么说?

The number of the apples is five.在这里我们把the number of the apples 看作是一个整体，（即单数）所以用is.

the number of the apples is 5.
什么什么的数量用the number of sth
后面接单数,用is.

类似的,
a number of和a lot of 同意
后面要用复数.比如 "a number of apples"意思是"很多苹果".

应该是复数的。注意单数复数的用法：
There are 5 apples.

The quantity of the applys is five.
the number会被理解为苹果的号码或编号.而不是数量.

The number of the apples is 5.

The amount of the apples is five.