41.  There must be something that only men can do, on the contrary, so does it.

42.  For a human being to lead a total life, he or she must have both forms of energy: the power of strength and the power of subtlety; the power of giving and the power of receiving.

43.  In such a situation, the two parties must be comfortable with the arrangement and they must respect each other and help each other along.

44.  If a person only has the typical characteristics of men or women, he or she must be isolated and uncompleted because a perfect one would try to cultivate all the brilliant characteristics belonging to the entire human beings.

45.  Many occupations seldom employ women, while some other occupations must be taken by women.

46.  My answer must be "yes".

47.  If you want to go abroad, or take up advanced studies, or even answer a foreigner's simple question when you walk on a street, you must use English.

48.  Our teacher will give us a variety of reading materials and all-round training, so I must do my best to follow her.

49.  Therefore, in the coming three years , I must shoulder the burden of escalating my listening and speaking gradually.

50.  Nevertheless, as we all know that only men and women must cooperate with each other can they stimulate prosper of the society and create happy families.