2. Literature Review
2.1 Eugene Nida’s Functional Equivalence
  The Functional equivalence theory is one of the most important translation theories, whose purpose is to achieve maximum information equivalence between a source text and its target text. Functional equivalence theory makes a great breakthrough to traditional translation principles, bringing modern linguistics, communication theory, information theory, semiotics and aesthetics into the field of translation, and providing a new perspective for translation research. It has undergone several stages of development.
2.1.1 The initiation stage
  The Functional Equivalence theory starts with Eugene Nida who is a linguist and one of the founders of the modern translation discipline. At the beginning ,the theory was used in translating Bible .Translators of the Bible have taken various approaches in rendering it into English, ranging from an extreme use of Formal Equivalence, to extreme use of Dynamic Equivalence(Guan Lin,2008) and at last this kind of translation vision was wildly accepted by people. The two terms of Formal Equivalence and Dynamic Equivalence have often been understood as fundamentally the same as sense-for-sense translation (translating the meanings of phrases or whole sentences) and word-for-word translation (translating the meanings of inpidual words in their more or less exact syntactic sequence), respectively. Nida’s original definition of dynamic equivalence was rhetorical: “the idea was that the translator should translate so that the effect of the translation on the target reader is roughly the same as the effect of the source text once was on the source reader (Wikipedia, 2015)”. For example，“white as snow”  can be readily translated as “白如雪”, but most Chinese people would rather have a simpler and more compact version, “雪白”.
2.1.2 Development
   As time goes by, Nida distanced himself from the term “dynamic equivalence” and preferred “functional equivalence”. The term “functional equivalence” suggests not just that the equivalence is between the function of the source text in the source culture and the function of the target text (translation) in the target culture, but that “function” serves as a property of the text (Nida, 2004). The theory indicates that the translator should translate the source languages so that the effect of the translation on the target reader is roughly the same as the effect of the source text. The translator should trigger the deep meaning of the source text and project it into the target text. An excellent translation work should convey both the linguistic, formal (stylistic), cultural as well as aesthetic meaning of the target language.

2.1.3 Current situation
  Nowadays, the Functional Equivalence theory has become an important theory in translation. It is wildly used in lyrics, poem and film translating. For example, Functional equivalence is always the standard of film subtitle translation, which has an important guiding role on the translation. Functional equivalence theory is also used in brand translation, which makes the brand can be easily understand and accepted by people. 功能等值理论指导下的鲍勃迪伦英文歌词翻译(2):http://www.youerw.com/yingyu/lunwen_23664.html