adj.四倍的；四重的
adv.四倍地；四重地

The company's profits increased fourfold in the past year.
公司在过去一年中的利润增长了四倍。
We need to increase our efforts fourfold to meet the deadline.
为了赶上截止日期，我们需要加倍努力，提升至原来的四倍。
The city's population has grown fourfold since the turn of the century.
自世纪之交以来，这个城市的人口已经增长了四倍。
He improved his running time by fourfold after months of training.
经过几个月的训练，他跑步的时间提高了四倍。
Our production capacity has expanded fourfold, enabling us to serve more customers.
我们的生产能力扩大了四倍，使我们能够为更多的客户提供服务。
The demand for organic food has increased fourfold over the last decade.
过去十年间，对有机食品的需求增长了四倍。
She was given a fourfold salary increment after winning the employee of the year award.
在赢得年度优秀员工奖后，她的薪水提高了四倍。
His responsibility at work multiplied fourfold when he got promoted to manager.
当他晋升为经理时，他在工作中的责任增加了四倍。
Due to budget cuts, we have to reduce our expenses fourfold to stay within our means.
由于预算削减，我们必须将开支压缩到原来的四分之一才能维持收支平衡。
With the introduction of new technology, their productivity has risen fourfold.
随着新技术的引入，他们的生产效率提高了四倍。