题目

— Excuse me, is Michael in black pants now? — No. He's in ____ coat and ____ pants now. A . black; a white B . a black; white C . black; white D . a black; a white 答案：B（2003•绵阳）如图，PA、PB是⊙O的两条切线，A、B为切点，则∠ABO-∠ABP=    ．