aeons of geological history数以亿万年计的地质史Aeons ago, there were deserts where there is now fertile land.现在是肥沃土地的地方在很久很久以前曾是一片片沙漠。She recalled her talk with him aeons ago.她回忆起许久以前和他的谈话The hour passed like aeons.时间过得慢极了。...
The authors show that the hyperboloid of one sheet and the hyperbolic paraboloid are ruled surfaces.作者证实:单叶双曲面和双曲抛物面是直线曲面.Two fdmilies Of characteristic lines in the hyperbolic region are not orthogonal.在双曲型区域两族特征线互不正交.F...