fourfold

形容词 fourfold:

1. four times as great or many
   同义词：quadruple, four-fold
2. having four units or components
   同义词：quadruple, quadruplicate, quadruplex, four-fold

副词 fourfold:

1. by a factor of four
   同义词：four times

1. In some cases output has increased more than fourfold.
   在有些情况下，产量增加了3倍多。
2. The population in this area has increased fourfold.
   该地区的人口已增加到四倍。