判断正误并改错
71. It is an accepted custom for guests to take their gifts to the wedding reception when the couple invited them to attend.   
72. Some international students use a cassette recorder to make tapes of their classes so that they can repeat the lectures again.
73. Despite of diligent efforts to promote domestic production during the war years，the Continental Army had to rely primarily on captures and imports for much of its military hardware and even for clothing.
74. In a sense，farmers began primitive genetic engineering at the dawn of agriculture，which they kept seeds from their best plants，gradually improving the quality of successive generations. 
75. Students completing a course in computer science and technology can look forward to find a wide range of jobs.             
76. The departments concerned shall listen and accept criticisms and rational suggestions regarding the protection of women’s rights and interes.
77. Astronomers have increased their observation powers greatly through improved high-
-powered telescopes，computer simulations and coordinate with other scientists.
78. In business as a whole，there is a controversy as to whether are businesses really encouraging the prospects of greater equality in the workplace.
79. It is ironic that although in 1955 actor James Dean made an advertisement warning teens of how harm it was to drive fast，he himself died from a speeding accident.
80. Neither of the boys who have been helping us know the importance of this particular project.

参考答案及解析
71. C错，应改为invites。因为该句是在陈述一个现在的事实，时态应该用一般现在时。
72. D 错，again 与repeat重复，应去掉。
73. A 错，Despite of改为Despite。此句混淆了despite和in spite of的用法。
74. B错，which改为when。此处的先行词是个时间状语，所以从句中应该选用关系副词。
75. C错，find改为finding。look forward to中的to是介词，所以后面出现动词时应用动名词形式。
76. A错，listen改为listen to。listen 是不及物动词，后面出现宾语时，需要相应的介词to。
77. D错，coordinate改为coordination。and连接的是并列成分，所以此处需要的是两个并列名词。
78. C错，are businesses 改为businesses are。从句中应该用陈述语序。
79. B 错，how harm改为how harmful。此处是感叹句，how修饰的只能是副词或者是形容词。
80. C 错，know改为knows。如果neither做主语，谓语应该用单数。