1、如果不特定指出哪一个，是泛指，“另一个”要用another, 后加可数名词单数。

If you are still thirsty, you may have another cup of tea.(没特定指出哪一杯茶，是泛指。cup是单数。)

another也可+数字+可数复数：The meeting will last another two hours. (再持续两小时)

We need another six desks. (此处两句分别相当于：two more hours; six more desks.)

2、如果只有两个或只有两部分，就给出了范围，其中另一个或另一部分是特指 (other前有the.)， 有如下用法：

第一种，所说内容只有两个：Mrs. Green has two sons, one is interested in math, the other (one/son) is good at science. 【只有两个，用the other, 不加s, 后面名词可省略。】又如：This pair of shoes is strange. One is blue, yet the other is green. “这双鞋子很怪，一只蓝色，而另一只绿色。”第二种，只有两部分：此种情况下the other后接可数名词复数，或不接名词而只在the other后加s. Two children went there, but the other children/the others stayed.

Two fifths of the students in our class are boys, the other students/the others are girls.

3、如果没有显示出只有两部分，未给出范围，则是泛指，不加the.

Lei Feng liked helping other people/others. Do you have any other questions?

Alice didn’t like that dress, so she asked to see some others.

other的另一用法：用比较级的形式，体现最高级的含义。

He is taller than any other boy in his class. (划线中boy常用单数) =

He is taller than all ( of ) the other boys in his class. (划线中boy用复数)

他比班里任何男孩都高(他是班里男孩中最高的)。