近鸟龙的腕骨呈深楔形，因此它可以将前肢折叠到身体两侧，行走时前肢上的羽毛可以悬空，不会拖在地面上。
Anchiornis's wrist bone was so wedge-shaped that it could fold its arms to its sides, keeping its arm feathers off the ground as it walked.
代数学,据约翰·德比夏尔所说,可以追溯到古巴比伦人留在楔形文字石碑上的简单的代数问题.
THE roots of algebra, asJohn Derbyshire tells us, go back to the ancient world: the Babylonians leftcuneiform tablets showing simple algebraic problems.
不论从前面还是从侧面观察头部，共同之处在于都可以明显地观察到倾斜的楔形，轮廓平顺。
When viewed from the front or the side the head bears a general resemblance to a well-blunted clean wedge, being smooth in outline.
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