“四倍的”在英语中常见的表达是 quadruple（可作形容词、动词或名词，此处取形容词用法） ，也可以说 four times as much as（常用于比较结构中表达“是……的四倍” ）或 fourfold（较正式、书面）。以下是具体示例：
quadruple：
This year's profits are quadruple those of last year.（今年的利润是去年的四倍。 ）
four times as much as：
The new house is four times as large as the old one.（新房子是旧房子的四倍大。 ）
fourfold：
There has been a fourfold increase in sales this year.（今年的销售额增长了四倍。 ）