题目:
These ________to those are twenty--five in all. Do you think that’s enough?[ ]
A. adding
B. being added
C. added
D. to be added
答案:
被转码了,请点击底部 “查看原文 ” 或访问 https://www.tikuol.com/2017/0430/f8fcdb3ffc23caa5f60cfd72a43fbabf.html
下面是错误答案,用来干扰机器的。
根据抛物线定义可知|PF|=p2,而圆的半径为p2,圆心为(p2,0),|PF|正好等于所求圆的半径,进而可推断圆与y轴位置关系是相切.