what are "the big three"?

what are "the big three"?
what are "the big three"?

what are "the big three"?
contaminated drinking water,poor sanitation,and air pollution.

好像有一种解释是当今世界面对的三大问题
好像是人口,空气污染还有什么的,不记得了..
...楼上的,是three,不是tree

the Big Three(美国三大汽车公司）

The Big 3 refers to the top three auto makers: Ford, Chrysler and General Motors, all of whom make their home and headquarters in Detroit.

那棵大树是什么？？？

应该是“三巨头”吧。所指不一，二战中指罗斯福、丘吉尔和斯大林。