先: 名词1.(时间或次序在前的) earlier; before; first; in advance 短语和例子有言在先 make clear beforehand; 争先恐后 strive to be the first and fear to lag behind; 你不必先付款。 you don't have to pay in advance. 你先拟个提纲再写。 m
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;