但是话又说回来，你不掌握也没有太大关系。你可以换成别的词儿，你可以不用，你可以说温室气体嘛。二氧化碳其实在全球变暖过程中就是起到一个温室气体作用。Green house gas 那你就解释出来呗，氟利昂不会就不说了。你可以说点儿别的话，作文有很大主观能动性的。那么Green house gas 你真的会吗？gas 你真的会吗？还有更多的常见词，你是不是会写呢？比如说，像使用空调啊，使用私人小汽车啊，是我们的生活变得更方便，这种词儿你真会吗？你不信你自己写一下。

　　要背的第2个方面——常见词。

　　常见词是哪一些，有个最简单的描述叫大学英语积极词汇，在我的博客中就能找到。其实大家在网上各处都能找到大学英语积极词汇。就是用得比较多的常见词，那么你把这些词给用好了，那绝对作文就没有太大的问题。

　　附：2009年6月六级写作真题参考范文

　　On the Importance of a Name

　　There is no denying the fact that it is a controversial topic whether names are important or not. Some hold the positive view. They claim that a good name, or a name that can be easily remembered, can bring one a lot more opportunities than others. Some Chinese may also believe that a name designed according to the traditional theory of five elements can bring good luck.

　　Others, however, hold the opposite view. They argue that a name is nothing but a code to distinguish one from another. A person “good” name may not be as successful as the name indicates. In the same way, a person who has a common or casually given name can also achieve tremendous success.

　　Personally, I believe that both sides have something right, so we should not go to extremes. On the one hand, we have to admit that a well designed name can help a person to some extent. On the other hand, we should not exaggerate the effect of a name on a person’s fate. Anyway, a person’s success mainly depends on his hard work and desirable personalities.（186 words）