请用本单元所学短语的适当形式填空。

Parents' behavior ________(有很大影响)their children．

以下是从本单元课文中摘出的原句。试试看，能填上吗？要注意词形变化！

1．College students can check the card ________ of libraries of different countries to finish their papers．

2．However, everything good has its ________．

3．________ personal communication, the Internet could be the most convenient means, too．

4．How to ________ child web fans ________ unsuitable materials online while encouraging them to use the Internet has long been discussed．

5．If we tell our kids they can't ________ the Internet, we are ________ them ________ from their future．

请根据下列提示写出相应内容。

1．电子的adj．________→用电的adj．________→电n．________

2．松弛的，不紧的adj．________→放松，松开v．________

3．通路，入门n．________→存取(文件)v．________→可接近的adj．________

请根据下列提示写出相应内容。

1．error n．________

2．jungle n．________

3．engine n．________

4．便利，方便n．________→便利的，方便的adj．________

请根据下列提示写出相应内容。

1．network n．________

2．catalogue n．________

3．drawback n．________

4．globe n．________

请根据下列提示写出相应内容。

1．满意的adj．________

2．邻近的adv．/adj．________

3．可靠的adj．________

4．活动，行动n．________

请根据下列提示写出相应内容。

1．讨论，论述v．________

2．软件n．________

3．选择，挑选v．________

4．限制，限定v．________

请根据下列提示写出相应内容。

1．邮件，邮寄n．/v．________

2．手段，方法n．________

3．保护v．________

请根据下列提示写出相应内容。

1．后者n．________

2．连结，联合v．________

3．机构n．________

4．情报，信息n．________

阅读下面短文，用适当的词填空。

　　Trees are useful to human beings in three important ways：they 　　1　　 them with food and other produces; they give them 　　2　　; and they help to 　　3　　 floods．　　4　　 in many parts of the world, people haven't realized that the 　　5　　 of these services is the most important．To get quick profits from the tree, they have cut them in 　　6　　 numbers, only to find that they have 　　7　　 their good friends．Two thousand years ago a rich and 　　8　　 country cut down its trees to build warships, with which it seized an empire．It gained the empire, 　　9　　, without its trees, its 　　10　　 became hard and poor．When the empire fell to pieces, the home country found itself faced with floods and starvation．

　　It is difficult for the government to 　　11　　 the villagers to see this．They are usually too lazy or too careless to plant and look after new trees．　　12　　 the government has a good system of control, the forest will slowly 　　13　　．This does not only mean that the villagers' sons and grandsons will have fewer trees．The results are even more 　　14　　．Where there are trees, their roots break the soil up－allowing rain to sink in．The roots also bind the soil, 　　15　　 preventing it from being washed away easily．If there are no trees, rain falls on hard ground and flows away from the surface, carrying away with it, the rich top-soil．When all the top-soil is gone, nothing 　　16　　 but a worthless desert．

1．________　2．________　3．________　4．________　5．________

6．________　7．________　8．________　9．________　10．________

11．________　12．________　13．________　14．________　15．________

16．________