题目

No one can be ______ for the work ________ he is .     A. more fit , than                                       B. fit , than     C. more fit , as                                         D. more fit , like 答案：A若∆ABC的内切圆半径为r，三边长为a、b、c，则∆ABC的面积S＝r (a+b+c) 类比到空间，若四面体的内切球半径为R，四个面的面积为S1、S2 、S3 、S4，则四面体的体积V＝                 ．