引: Ⅰ动词1.(牵引; 拉) draw; stretch 短语和例子引弓 draw a bow2.(引导) lead; guide 短语和例子引路 lead the way; 他把我引进会客室。he ushered me into the reception room. 一条沟把溪水引到田间。a ditch diverted water from the stream into
垂直: perpendicular; vertical; squareness; verticality; perpendicularity 短语和例子两线垂直相交。the two lines meet at right angles. 设 ab 垂直于 cd。let ab be perpendicular to cd. 当表面与射线垂直时，射线的强度最大。when a surfa
