“三倍数”常见的英文表达是 “triple” (既可以作名词,也可以作形容词)或者 “three times the amount/number”(更正式、明确的表达结构) 。
用“triple”:
The new model's speed is a triple of the old one.(新型号的速度是旧型号的三倍。这里“triple”作名词,表示“三倍量” )
This year's profit is triple last year's.(今年的利润是去年的三倍。这里“triple”作形容词,修饰“last year's”所代表的利润 )
用“three times the amount/number”:
The population of this city is three times the amount of ten years ago.(这个城市的人口是十年前的三倍。 )
The cost of this project is three times the number we initially estimated.(这个项目的成本是我们最初估计的三倍。 )