系统软件 操作系统 释文 real-time system executive 实时系统执行体
- pencil of conics
- pencil of curves
- pencil of hyperplanes
- pencil of lines
- pencil of matrices
- pencil of operators
- pencil of parallel lines
- pencil of pencils
- pencil of planes
- pencil of quadrics
- pencil of rays
- pencil of spheres
- pencil of surfaces
- pencil rocket
- pencil section
- pencycuron
- pendant
- pendant drop method
- pendant edge
- Pendant Representing The Head of Acheloos
- pendant vertex
- peNDF
- pendimethalin
- Pendjari National Park
- Pendleton Act