题目

______ is good at all things at birth. You can do anything well if you are willing to put your heart into it. A. Anybody               B. Everybody                C. Somebody                D. Nobody 答案：D2．已知直线l：ax+by+c=0及圆P：x2+y2=1，其中a，b，c满足条件：a2+b2=k2c2，其中（c≠0，k≠0）（1）试讨论直线l与圆P的位置关系，（2）若直线l被圆P截得的弦长为1，求k的值．