据《乐记·乐论》载：乐者天地之和也；礼者，天地之序也。和，故百物皆化；序，故群物皆别。乐由天作，礼以地制。过制则乱，过作则暴。明于天地，然后能兴礼乐也。该材料（    ）

2011年云南曲靖的铬（Cr）污染事件，说明含铬废渣（废液）的随意排放对人类生存环境有极大的危害．电解法是处理铬污染的一种方法，其处理过程发生的反应可表示为：

6Fe+K₂Cr₂O₇+H₂SO₄+17H₂O=6Fe（OH）₃↓+2Cr（OH）₃↓+6X+K₂SO₄

    Mails, games, music, news, chat rooms and shopping! The Interent is part of our life today. It's easy to get onto the Internet. The only thing we need to do is to use a modem(调制解调器) which is used for connecting a computer to a telephone line. The Internet is changing and growing all the time. More and more people have computers and use the Internet. Using the Internet means surfing the World Wide Web(That's the “WWW” you always hear about). The Internet has a large number of websites(网站). They are the places where you go to get information and do things.
     Where do these websites come from? They are made by web designers. What happens when you click on a word or a picture? You are sent to another page. It's all because of the web designers. Web designers do a lot of work by using a computer programming(程序编制) language.
     Is web design all about computer programming? No, it's about making something new. Web designers must imagine a lot when they are making a website. It must look good and be fun to use. A big part of web design is art. They choose the best pictures and colors to make the website look good. They also write the things that you see on the website. An important part of their job is to share ideas with the website manager about how to design the website well.