题干

Everyone knows that________ is dangerous to play with fire, but________ is difficult is to prevent children from playing with fire.
A.it; what B. what; what C. what; it   D. it; it
上一题 下一题 0.65难度 单项选择 更新时间:2013-05-26 12:47:16

答案(点此获取答案解析)