字长差别并不是很大：被研究的演讲中，所用的单词，平均字长为4.5个字母。
Word lengths do not differ much: the average word used in the speeches analysed had around 4.5 letters.
统计结果证明，从字词频率、平均字长和句长这些语言变量方面讲，六级作文的语言水平略高于四级作文。
The result indicates that CET6 writers show higher language proficiency from the perspective of word frequency, average word length and sentence length.
第五章作业编写一个程序，对输入的图像进行哈夫曼编码，显示原图像的熵、编码后的平均码字长度、并能够根据编码重建出图像。
Chapter operations to write a program, the input image Huffman, display the original image entropy encoded average code word length, and be able to reconstruct the image according to encoding.
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