right-angled screwdriver是什么意思

用法例句

By introducing the concepts of obtuse cone and orthogonal cone,this paper analyzed the connection between the cone and dual cone.

通过引入钝锥和直角锥的概念,阐述了锥与对偶锥之间的关系,并给出了钝锥和直角锥存在的充分必要条件。