It was ( )difficult work that i can not work it out 括号里填什么?S

It is _question that i can't work it out.A.a so difficult B. the-----is very difficult,I can not work it out用question 还是p The problen is difficult.I can't work it out. i can't work out the problem.it's too difficult同义句转换 i have 1.The math problem is so difficult that I can't work it out. The problem is so difficult that I can't work it out.同义句 The problem was so difficult that we couldn't work it out ea The problem is so difficult that nobody can work it out(改为同义 This problem is so difficult that nobody can work it out. This problem is so difficult that we can't work it out.(保持句意 This problem is so difficult that nobody can work it out.(保持 It is such a difficult problem___nobody can work out.