I gave her a lift back out to her house.我让她搭我的便车回家。Once you've given your word, don't try to back out.一旦许下诺言, 就不要想翻悔.We drove into a dead end and had to back out.我们把车子开进了一条死胡同,只得退出来....
多角形的边界可以延伸到无穷远处.Boundaries of the polygon may extend to infinity.颗粒呈简单的多角形.The grains take on simple polygonal.这些名建筑是以圆形和多角形为基础而设计建造.These famous buildings are based on circles and polygons....