21. cook, cooker

cook廚師;
cooker廚具 eg:He is a good cook.

22. damage, damages

damage不可數(shù)名詞, 損害，損失;
damages復(fù)數(shù)形式, 賠償金 eg:$900 damages

23. police, policeman

police警察的總稱，后接復(fù)數(shù)謂語動詞;
policeman 指某個具體的警察 eg:The police are questioning everyone in the house.

24. problem, question

problem常和困難連系，前面的動詞常為think about, solve, raise;
question常和疑問連系，多和ask, answer連用