【正文】 t mutual and pete. Nida’s formal equivalence and dynamic equivalence As Belloc (1924) stated: “There are, properly speaking, no such things as identical equivalence”, so, one must in translating seek to find the closest possible equivalence. Thus, Nida states two kinds of equivalence in his book Toward a Science of Translating, namely, formal equivalence and dynamic equivalence. Formal equivalence focuses on the message itself, in both form and content. With this approach, one is concerned with the correspondences such as poetry to poetry, sentence to sentence, and concept to concept. Viewed from this formal orientation, one is concerned that the message in the receptor language should match as closely as possible the different elements in the source language, which means, for example, that the message in the receptor culture is constantly pared with the message in the source culture to determine standards of accuracy and correctness. On the other hand, dynamic equivalence is based upon the principle of equivalence effect. In such translation, instead of paying much attention to the match between the TL message and the SL message, the translator has to be more concerned with the dynamic relationship between receptor and message which should be substantially the same as that existing between the original receptors and the message. Functional equivalence—the further development of dynamic equivalence The concept of functional adequacy in translating has been described in a number of Nida’s books as “dynamic equivalence” while in From One Language to Another (1986), Nida changed the term “dynamic” into “functional”. Later in his book Language, Culture, and Translation (1998), he explained for the change that the term “dynamic” has been misunderstood by some persons as referring only to something which has impact. Accordingly, many individuals have been led to think that if a translation has considerable impact then it must be a correct example of dynamic equivalence. Because of this misunderstanding and in order to emphasize the concept of function, it has seemed much more satisfactory to use the expression “functional equivalence” in describing the degrees of adequacy of a translation.Nida states that since no translation is ever pletely equivalent, it is best to speak of “functional equivalence” in terms of a range of adequacy. A number of different translations can in fact represent varying degrees of equivalence. This means that “equivalence” cannot be understood in its mathematical meaning of identity, but only in terms of proximity. Such a view of functional equivalence implies different degrees of adequacy from minimal to maximal effectiveness on the basis of both cognitive and experiential factors. A minimal, realistic definition of functional equivalence could be stated as “The readers of a translated text should be able to prehend it to the point that they can conceive of how the original readers of the text must have understood and appreciated it.” Anything less than this degree of equivalence should be unacceptable. (Nida, 1969:116)A maximal, ideal definition could be stated as “The readers of a translated text should be able to understand and appreciate it in essentially the same manner as the original readers did.” The maximal definition implies a high degree of languageculture correspondence between the source and target languages and an unusually effective translation so as to produce in receptors the capacity for a response very close to what the original readers experienced. This maximal level of equivalence is rarely, if ever, achieved, except for texts having little or no aesthetic value and involving only routine information. (Nida, 1969:116) The reasons for functional equivalence as guideline in advertisement translation Among many of the theories and principles for translation that have been proposed by different scholars, the author views Nida’s functional equivalence theory as the guideline in advertisement translation, and for this, there are sufficient reasons as follows: First of all, functional equivalence fulfills the informative function of advertising. As we have mentioned, one of advertising’s function is to inform customers of the latest products and services. Advertising is actually a means for the advertisers to municate with the customers, and according to Nida, the final goal of translating of functional equivalence is to achieve plete munication between the author and the reader and to convey exactly what the author is attempting to convey to the reader. Thus, from this point of view, functional equivalence should be adapted as the guideline in ad translation. Secondly, the term “Readers’ responses” fits advertisement translation. According to Nida, purpose of achieving functional equivalence, what a translator should put in first priority is readers’ responses。 also, the quality of a translation should also be measured by readers’ responses, like he says (2001:116)“it is essential that functional equivalence be stated primarily in terms of a parison of the way in which the original receptors understood and appreciated the text and the way in which receptors of the translated text understand and appreciated the translated text”. It is known to us that all ads are created for consumers, the whole processes of advertising, like, media selecting, and copy writing must take the target audience into consideration. An ad translator, certainly, has to consider the readers, such as their educational backgrounds, religions, customs, and consumer behaviors, etc. What’s more, testing the translation of an ad does not consist in merely the parison of texts to see the extent of verbal consistency or conformity, but in determining how its target audience reacts to it. The translation of an excellent ad which cannot fulfill its original function and achieve the effect it is supposed to achieve cannot be regarded as