1、Everyone knows that _____ is dangerous to play with f

1、Everyone knows that _____ is dangerous to play with fire,but _____ is diffrcult is to prevent children from playing with me.A、itit B、whatwhat C、itwhat D、whatit2、But for the help you gave me,I _____ the exam nations.A、would have passed B、would pass C、wouldn't have passed D、wouldn't pass3、They told me it would be cheap but _____ it cost me nearly