31. a number of, the number of

　　a number of許多，謂語動詞用復(fù)數(shù)。the number of…的數(shù)目，謂語動詞用單數(shù)。The number of students isincreasing.

　　32. in front of, in the front of

　　in front of范圍外的前面，in the front of范圍內(nèi)的前面 Inthe front of the room sits a boy.

　　33. of the day, of a day

　　of the day每一天的，當(dāng)時的，當(dāng)代的， of a day暫時的，不長久的 a famous scientist of the day

　　34. three of us, the three of us

　　three of us我們(不止三個)中的三個，the three of us我們?nèi)齻�(就三個人)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，不用冠詞，on the bus表范圍 They went there by bus.

　　36. for a moment, for the moment

　　for a moment 片刻，一會兒，for the moment暫時，一時 Thinking for a moment, he agreed.

　　37. next year, the next year

　　next year將來時間狀語，the next year過去將來時間狀語 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超過一年(兩年或三年等)

　　39. take advice, take the(one's) advice

　　take advice征求意見，take the advice接受忠告 He refused to take the advice and failed again.

　　40. take air, take the air

　　take air傳播，走漏，take the air到戶外去，散步 We take the air every day.