A:Yes , he isn't .
B:No , he isn't .
C:No , she isn't
已知直线l:kx+y﹣2=0(k∈R)是圆C:x2+y2﹣6x+2y+9=0的对称轴,过点A(0,k)作圆C的一条切线,切点为B,则线段AB的长为( )
下列有关安全用药的叙述,错误的是( )