so difficult 和too difficult 和very difficult 和much too diffic

都对.
例句：
The question is so difficult that nobody here can answer it.
The work is too difficult to be solved by high school students.
The question is very difficult but I think I can handle it
The question is much too difficult for you as you are still a child.

问题再讲清楚些。。。。。。。。。。。

都对的，难的程度从低到高排序very difficult ，so difficult ，too difficult ，much too difficult。其中使用前两个时表示虽然很难，但还是有可能克服的，后两个就是难的不可能解决了