Different explanations are offered for America's weight problem a problem increasingly shared by other countries.

VOA: special.2009.08.06

And inside of each of these cups is a different weight so that in theory all of these cups are different weights.

每个杯子里的东西重量都不同,这样，从理论上看，这些杯子的重量都不同。

哈佛公开课 - 计算机科学课程节选