A translator is not supposed to add any meaning to or subtract any meaning from the original work. This is a principle not to be violated in translation. However, it does not follow that a translator should refrain from supplying the necessary word(s) to make his version both accurate and in keeping with the usage of the language translated into. Generally speaking, in English-Chinese translation "amplification" is often to be employed in the following cases :
(a) When some words are "syntactically omitted" in English.
例1："When trying to decide whether an object will float in water, you need to know whether its density is greater or less than that of water. If it is greater, the object will sink. If less, the object will float." In this case, "it is" and "than that of water" have been "omitted syntactically", the latter should normally be supplied in the Chinese version, to conform to the Chinese usage. Hence the Chinese version:“若要判断一个物体是否会在水中浮起，就得知道该物体的密度比水大还是比水小。要是比水大，该物体会下沉，要是比水小，就会浮起。”
(b) When a “pronoun” is used in the English sentence to avoid repetition (and，the wide use of pronouns is another special feature of English when compared with Chinese).
例2：“Some jets travel faster than sound. Then we shall not hear them until they have gone. ”
(c) When the relative pronoun or relative adverb is used to introduce a "nonrestrictive" clause, it often needs "amplification" in the Chinese version.
例3：“Yesterday we went to their laboratory，where we saw some sophisticated microcomputers newly designed by them. ”