31.  words are really important, learning many words is necessary for us , in my high school years, my english teacher told us that , he once had a student, the student tried to memorized a whole english dictionary, \

32.  some words are rare, maybe you can see them only once in your life, it's only for particular writing , it's not for speaking.

33.  Jim and Della used the most precious thing in exchange for what his or her partner once wanted to have--Jim sold the gold watch to buy the set of combs Della had worshipped long in a Broadway window, while Della's beautiful hair was sold to make enough money for a platinum fob chain that must matches Jim's gold watch well.

34.  I have imaged the life in college more than once.

35.  As we all know, every one may forget some thing that he once remembered .

36.  It is so hard to remove so many differences and such change will never be a business once for all.

37.  Adam Smith once proposed the theory of division and cooperation of labor, which insisted that if anyone focused on producing the thing he was good at, the overall and individual efficiency would be soared, so would a country.

38.  I once think college life is free and colourful.

39.  I once imagined college is where students can be very free.

40.  As is mentioned above, the words which are memorized by looking through word lists again and again will be easy to forget once not used every so often, which will do nothing to enlarge your vocabulary.