有三种尺寸—小号、中号和大号。

There are three sizes—small, medium and large.

《牛津词典》

正方形、圆形和三角形是三种形状。

Squares, circles and triangles are types of shape.

《牛津词典》

解决这个问题有三种根本不同的方法。

There are three essentially different ways of tackling the problem.

《牛津词典》

Scholars have proposed three possible models to explain the formation of Israel. The first is an immigration model.

学者们提出了三种可能的模型,来解释以色列的形成，第一种是移民模式。

耶鲁公开课 - 旧约导论课程节选

But, if you look more carefully, you will find that this is a blend of three different forms of carbon.

但是，如果你们再认真一点，会发现,它是三种形式的碳的混合物。

麻省理工公开课 - 固态化学导论课程节选

These three lights with their respective colors just do positively mean these things.

三种颜色的灯和它们各自的颜色,自然的有各自表达的意思。

耶鲁公开课 - 文学理论导论课程节选