First, I expounded on the purpose and significance of learning disability revie-wed the history of China in the level of learning disability Health research and paper used by the research methods.

本文首先阐明了研究的目的和意义，回顾了学习困难研究的历史、我国对中职生学习困难的研究状况及本文所使用的研究方法。

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This paper analysed the loud composition food type, nutritional grade, food wed and food competition of the fishes inBaiyangdian Lake.

本文分析了白洋淀鱼类的食物组成、食性类型、营养级、食物网及食物竞争。

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