“Cool” is a word with many meanings, (1) As the world change, the word has many different meanings. “Cool” can be used to express feelings of interest in almost anything. When you see a famous car on the street, maybe you will say, “It’s cool.” (2) You can use “cool” instead of many words. (3) A teacher asked her students to write about the waterfall(瀑布) they had visited.On one student’s paper was just one sentence,“ It’s so cool.” (4) But the story also shows a scarcity(缺乏) of words. Without “cool”, some people have no words to show the same meaning. (5) I can. And I think they are also very cool.