■ accident

也可以不是“事故”，而是“尿了床”，或是“尿了裤子”。

• The child had a little accident.孩子尿了裤子了。
• Should you have an accident, synthetic quilts are quite easy to wash.万一尿了床，化纤被子是很容易洗的。

• unaware
• unawares
• unaware 与 unawares
• under
• under-
• underestimate
• undersell
• unhuman
• unilateral
• unilateral 与 one-sided
• uninterested
• union
• unite
• united states
• university
• unless
• unlike
• unload
• unsatisfied
• until
• until
• until
• uphill
• up north
• upon