something什么情况下变为anything

something什么情况下变为anything
怎么在一道题 I know ____ about your hobby.Could you tell me ____about A.angthing;anything B.nothing;something C.something;angthing D.something;something 这题答案选B、问一下大家这题后半空如何分析、不是说在否定句中something转换成anything吗?