A number of staircases ascend from the cobbled streets onto the ramparts.一段石阶从鹅卵石路上一直向上直通城墙。Then we ascend steeply through forests of rhododendron.然后我们在杜鹃花丛中沿着陡坡向上爬。The path started to ascend more steeply.小径开始陡峭而上。...
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...