【还是同义句转换】the puzzle is so difficult that nobody can work it out.

问题描述:

【还是同义句转换】the puzzle is so difficult that nobody can work it out.
the puzzle is______ _______ _______ ______that no one can work it out.每空一词
……我想用SO that来着,但是凑不够四个空……

我觉得用such a difficult one或者too difficult to us 应该都可以