本卷论述公元 906 年至公元 1279 年的中国历史。这是中国封建社会继续 向前发展时期的历史，也是中国各民族又一次重新组合时期的历史。汉族地 区经济重心的南移，南海贸易的畅通，边疆民族地区封建化的加深，都是前 所未有的。在学术文化方面，文、史、哲、理均有巨著，且树新声

袁绍（？—202 年），字本初，汝南汝阳（今河南商水西南）人，出身 于东汉后期一个势倾天下的世家。从他的高祖父袁安起，四世之中有五人官 拜三公。②父逢，官司空。叔父隗，官司徒。伯父成，官左中郎将，早逝。袁 绍庶出，过继于袁成一房

随父征战 拖雷（Tolui，1192？—1232），太祖成吉思汗第四子，蒙古人在他死后 避其名讳，称也可那颜（Yeke-noyan，“大官人”）①，世祖至元三年追谥景 襄皇帝，庙号睿宗②。母为大皇后弘吉剌氏孛儿台·旭真（borte-hujin，hujin 源于汉语“夫人”），在成吉思汗众多后妃中地位最尊，主第一斡耳朵，生 四子：术赤、察合台、窝阔台、拖雷，被称为四曲律（kulug，“骏马”、“豪 杰”）

这是《中国通史》第三卷，论述我国自有文字记载以来，一直到战国末 年的历史。从历史发展顺序上看，这约略相当于一般历史著述中所说的奴隶 制时代。但在这个时代，奴隶制并不是唯一的社会形态。我们用“上古时代” 的提法，可能更妥当些

满族领袖和清皇朝的始祖 爱新觉罗·努尔哈赤，征战四十余年，统一女 真各部，反抗明皇朝的民族压迫，保护了满族的生存，对满族的形成和发展， 对东北地区的统一和多民族祖国的壮大，起了重要的促进作用。他是中国历 史上杰出的政治家和军事家之一

32.1 Biologists name organisms in a systematic way. The Classification of Organisms. Biologists name organisms using a binomial system. Species Names. Every kind of organism is assigned a unique name. The Taxonomic Hierarchy. The higher groups into which an organism is placed reveal a great deal about the organism

1.1 Biology is the science of life. Properties of Life. Biology is the science that studies living organisms and how they interact with one another and their environment

When Mendel did his crosses of pea plants, he knew what a pea plant was supposed to look like: a small plant with green leaves, purple flowers, and smooth seeds. But if all pea plants were like that, he would never have been able to sort out the rules of heredity—in a cross of green peas with green peas, there would have been no visible differences to reveal the

In class, we saw the connection between the so-called Hermite matrix and the semi-circular law. There is actually a deeper story that connects the classical random matrix ensembles to the classical orthogonal polynomials studied in classical texts such as [1] and more recent monographs such as

1 The eigenvalue distribution function For an N × N matrix AN , the eigenvalue distribution function 1 (e.d.f.) F AN (x) is defined as F AN (x) = Number of eigenvalues of AN ≤ x . (1) N As defined, the e.d.f. is right continuous and possibly atomic i.e. with step discontinuities at discrete points. In practical terms, the derivative of (1), referred to as the (eigenvalue) level density, is simply the