difficultyn.困难;争议;麻烦
differentiatevt.区分;使差异;求导数vi.区别;产生差别;区别对待
difficult of难以, 很难
Difficultiea困难
difficultiesl问题
difficult job艰难的工作
difficultnessn.难;困难;费力
difficult man不易相处的男人
Difficult ore难采残矿
difficult task困难的任务
difficult work难念的经
difficult test要求高的测验