英语中关于倍数有几种表达方法？

1. 表示“几倍大小（长短；数量）”，由“倍数+ the size（length，amount……）”结构组成。例如：The earth is forth-nine times the size of the moon. 地球是月亮的49倍大。

2. 表示“……比……大几倍”，由“倍数+形容词（副词）比较级”结构组成。例如：This box is three times bigger than that one. 这个盒子比那个盒子大三倍。The grain output is 8 percent higher this year than that of last year. 今年比去年粮食产量增加8%。

3. 表示“……是……倍”，由“倍数+ as +形容词+ as +”结构组成。例如：Our factory is twice as big as theirs. 我们的工厂是他们的三倍。I have three times as many as you. 我有你三倍那么多。 [注] 一倍用once，两倍用 twice。 4、还可以用by+倍数，表示增加多少倍。The production of grain has been increased by four times this year. 今年粮食产量增加了4倍。