题目

We had to           the match as the ground was too wet to play on.    A. call off         B. call up           C. call out         D. call for 答案：A求棱锥的中截面把棱锥分成的两部分的体积比． 已知：如图，在棱锥S—AC中，截面AˊBˊCˊDˊEˊ是其中截面． 求：棱锥S—AˊCˊ与几何体AˊBˊCˊDˊ’ 一ABCDE(棱台)的体积之比．