题目

四、it类 . Everyone knows that _______ is dangerous to play with fire, but _______ is difficult is to prevent children from playing with fire. A. it, it            B. what, what         C. it, what                D. what, it 答案：DHe________ sing so________ as his brother．A.doesn’t，goodB.isn’t，goodC.isn’t，wellD.doesn’t，well