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
阶: 名词1.(台阶) steps; stairs 短语和例子石阶 stone stairs; 台阶 a flight of steps2.(等级) rank 短语和例子军阶 military rank3.[医学] (耳蜗的三个螺旋管的任一个) scala 短语和例子中阶 scala media4.[数学] order 短语和例子非整数阶 non-integral order;
