difficult

difficult dentition

[医] 出牙困难

difficult labor

[医] 难产

difficult menstruation

[医] 月经困难

difficulties

n. 困难( difficulty的名词复数 ); 难度; 难事; 麻烦

difficultly

adv. 难, 艰难, 困难, 难相处, 难弄

difficultness

n. difficult的变形