答案与简析：

　　76. famous前加上a。 （名词数）。 77. 正确 78. we前面加when，引导一个时间状语从句。（句子成分多分析） 79. them→us （逻辑错误须关注） 80. visiting→visited（非谓动词细辨别） 81. picture→pictures（名词数） 82. passes→passed（动词形） 83. 去掉down（习惯用法要记住） 84. and→but（but, and, or和so） 85. 去掉at（句子成分多分析 / 习惯用法要记住）。

 (一)

Most families in China hoped their single children will          76．_______

have a happy future, so they are very strict in their children.  77．_______

So do teachers in schools! Many children are given so much       78．_______

homework that they have hardly any spare time have sports.       79．_______

The children are forbidden to do anything but to study. No       80．_______

wonder so many children are tired of lessons. Some even          81．_______

attack or kill his parents and teachers! I believe many people   82．_______

already read this kind of news in newspapers or magazines.       83．_______

Shouldn't we draw lesson from the accidents? Now our             84．_______

government is making out a plan to solve the education problems. 85．_______

“It + be + 时间名词+before / since”从句句型中用before引导时，句意是 “过了多久才……”，主句中的be动词为过去时或将来时态；用since引导时，其句间是“自从……以来已经多久了”，主句中的be动词多为现在时(或现在完成时)或一般过去时。