（完成单词）It's n______ to protect our earth right now．

（完成单词）Don't do h______ to the environment．

（完成单词）We should buy p______ made in China．

（完成单词）Do you know the d______ between the Internet and the World Wide Web?

（完成单词）We should r______ waste and save energy．

（完成单词）It is h______，although we do something to make it better．

（完成单词）Now it gets warmer and warmer because the p______ is getting more seri-ous．

（完成单词）Don't throw away! It can be r______．

（完成单词）Heat is a form(形式)of e______．

You should look after the books well. (改为同义句)

　　You should ______ ______ ______ ______ the books．