阅读下面短文，从每题所给的A、B、C、D四个选项中，选出一个能填入文中相应空白处的最佳答案。
“If you agree with me，please Dianzan.”Do you know Dianzan is one of the most popular words on the Internet？When you think someone's ideas are right，when you think someone's articles are 1，or when you are moved by what someone writes，you can
click （点击）the praise sign. Anyhow，clicking the praise sign 2that you agree with someone or praise someone.
Dianzan is a kind of Chinese Internet language.People 3 use it when they surf the Liternet.There is a function（功能）of Dianzan in the QQ space.The QQ space has had the function 42010.It didn't become very popular until Sina blog（新浪博客）5the function of Dianzan.In recent years，it has become more and more popular.When the 2015 New Year came，Chinese leader Xi Jinping used the word Dianzan to praise and 6his thanks to the great Chinese people.
Websites can know how many people support some ideas 7counting how many people click the praise sign.Experts can know 8teenagers are caring about through what they click the sign for.That can help them solve teenagers'9.
Clicking the praise sign is really a（n） 10thing.Have you ever clicked the sign for anybody on the Internet
