21. cook, cooker
cook厨师，cooker厨具 He is a good cook.
22. damage, damages
damage不可数名词, 损害，损失; damages复数形式, 赔偿金 $900 damages
23. police, policeman
police警察的总称，后接复数谓语动词，policeman 指某个具体的警察 The police are questioning everyone in the house.
24. problem, question
problem常和困难连系，前面的动词常为think about, solve, raise，question常和疑问连系，多和ask, answer连用
25. man, a man
man人类，a man一个男人 Man will conquer nature.
26. chick, chicken
二者均可指小鸡，chicken还可以当鸡肉 The chicken is delicious.
27. telegram, telegraph
当电报解时，telegram指具体的，telegraph指抽象的 a telegram, by telegraph
28. trip, journey, travel, voyage
travel是最常用的，trip指短期的旅途，journey指稍长的旅途，voyage指海上航行 a three-day trip
29. sport, game
sport多指户外的游戏或娱乐活动，如打球，游泳，打猎，赛马等；game指决定胜负的游戏，通常有一套规则 His favorite sport is swimming.
30. price, prize
price价格，prize奖，奖品，奖金 win the first prize The price is high/low.
31. a number of, the number of
a number of许多，谓语动词用复数。the number of…的数目，谓语动词用单数。The number of students is increasing.
32. in front of, in the front of
in front of范围外的前面，in the front of范围内的前面 In the front of the room sits a boy.
33. of the day, of a day
of the day每一天的，当时的，当代的， of a day暂时的，不长久的 a famous scientist of the day
34. three of us, the three of us
three of us我们（不止三个）中的三个，the three of us我们三个（就三个人）The three of us---Tom, Jack and I went to the cinema.
35. by bus, on the bus
by bus表手段，方式，不用冠词，on the bus表范围 They went there by bus.
36. for a moment, for the moment
for a moment 片刻，一会儿，for the moment暂时，一时 Thinking for a moment, he agreed.
37. next year, the next year
next year将来时间状语，the next year过去将来时间状语 He said he would go abroad the next year.
38. more than a year, more than one year
more than a year一年多，more than one year超过一年（两年或三年等）
39. take advice, take the(one's) advice
take advice征求意见，take the advice接受忠告 He refused to take the advice and failed again.
40. take air, take the air
take air传播，走漏，take the air到户外去，散步 We take the air every day.
