We need to set about a solution.[ ]
A. to find
B. to finding
C. finding
D. find
答案:C
已知圆C:x2+y2+x-6y+m=0和直线l:x+y-3=0。
(Ⅰ)若圆C与直线l交于A、B两点,且CA⊥CB,求圆C的方程;
(Ⅱ)若圆C与直线l交于P、Q两点,是否存在m,使OP⊥OQ?
厚朴的药用部位属于( )
A.茎木类B.花类C.全草类D.根及根茎类E.皮类