欧几里德几何的唯一性与必要性已被公认.The common conclusion was the uniqueness and necessity of Euclidean geometry.非 欧几里德几何实际上是从属于欧几里德几何的.The non - Euclidena geometries were in effect subordinated to Euclidean geometry.这种几何和Riemann几何的关系是不清...
Tame birds, when approached, will stretch out their necks and ruffle their neck feathering.驯养的鸟儿在有人靠近时会伸长脖子，竖起颈羽。Mary's much more interested in doing things for other people than feathering her own nest.相比追逐私利，玛丽更乐意...