相关单词同義詞hard, tough, 近義詞 fussy, grim, hard, obscure, painful, steep, stiff, ticklish, tough, trying反義詞easy, straightforward臨近詞difficulty, differentiate, difficult of, Difficultiea, difficultiesl, difficult job, difficultness, difficult man, Difficult ore, difficult task, difficult work, difficult test相似詞differential calculus, differential gear, differentiate, differentiation, difficulty, diffident, diffract, diffraction, 返回 difficult