In E-C translation instruction studies, the influence of the sentence length has been extensively explored by the translation theorists. Most of them come to the conclusion that the sentence average length in translational Chinese is longer than that of the original Chinese, but few of them has explained how the long sentences are constructed and why. By comparing the differences in the sentence length and the internal grammatical structures of the long sentences between original Chinese and translational Chinese, this paper will verify the fact that the difference in the orders of the noun modifiers in English and Chinese contributes to the long sentences in translational Chinese, which should be particularly instructed in E-C Translation lessons.