Foursy富尔西
fournum.四
four color conjecture四色猜想
four-way connection四通连接,四通接头
four-toothed neriten.杂色蜒螺
four-level material四能级材料
four-color printing四色印刷法
four minutes response四分钟接警出动
four-speed gear box四速变速箱
Fourier decomposition傅里叶分解
four orthodox Caliphs四大哈里发
four species of Ficus4种榕树