71.It is only when these measures are put into practice that the shortage of water can be solved。

　　72.Only when a great deal more information has been obtained will it be possible to plan a manned trip to Mars。

　　73.Only when the old age problem is well handled can we maintain a stable and harmonious society。

　　74.Under no circumstances shall we give in to pressures or threats imposed by foreign countries。

　　75.Only when parents confront the problem seriously will the situation in which many children are denied a carefree vacation be reversed。

　　76.As long as the government and individuals strive hard, there will certainly be a way out for the laid-off workers。

　　77.Whatever changes are responsible for the rise in divorce rate, one thing is certain: there is a significant change in people’s traditional views of marriage and divorce。

　　78.In short(In a word/All in all/To sum up)， great efforts should be made to enhance ethic and moral education when high priority is given to the economic development。

　　79.If people from all walks of life pay enough attention to this problem, our life in the city will certainly be more enjoyable。

　　80.Judging from all evidence offered (From what has been discussed above)， we can safely come to the conclusion that coeducation is beneficial to the psychological and intellectual growth of both boy and girl students。

　　71。只有当这些措施付诸实践时，水资源的短缺才能得到解决。

　　72。只有当更多的信息获得时，才有可能筹划载人登月旅行。

　　73。只有当老龄问题得到很好的解决，我们才能保持一个稳定和谐的社会。

　　74。在任何情况下，我们都不能屈服于国外的压力或威胁。

　　75。只有当家长们认真对待这个问题时，孩子们被剥夺无忧假期的局面才能得以改正。

　　76。只要政府和个人都努力，就一定能为下岗工人找到出路。

　　77。不管离婚率上升的原因是什么，有一点是肯定的：人们对婚姻和离婚的传统观念发生了巨大的变化。

　　78。总之，当我们优先发展经济的时候，也要做出巨大努力来提高伦理道德的教育。

　　79。如果社会各个阶层的人们都能足够地重视这个问题，我们的城市生活将会变得更美好。

　　80。综上所述，我们可以得出这样的结论：同校教育(coeducation)对男孩和女孩的心理和智力的成长都是有益的。