difficulty

n.困难，难事；困境

diehard, dieresis, diesel, diesel-electric, diet, dietary, dieter, dietetic, dietetics, dietician (also dietitian), differ, difference, different, differential, differential calculus, differentiate, differentiated, differentiation, differently, difficult, diffidence, diffident, diffidently, diffract, diffraction, diffuse, diffusely, diffuseness, diffusion, dig, dig down, dig in, dig out, dig up, digest, digestibility, digestible, digestion, digestive, digestive biscuit (also digestive),