It is _question that i can't work it out.A.a so difficult B.so a difficult C.so difficult a 请帮我

It is _question that i can't work it out.A.a so difficult B.so a difficult C.so difficult a 请帮我 it is strange that 英语翻译it is( )( )that It is believe that It is said that. It is that all? it is imperative that? Is it that bad? it is discovered that that it is!和that's it! that it is!和that's it! it is ordered that,it is proposed that is all,that is it ,that is right 区别? It is amazing that 还是It is amazed that That is how it gose, it is high time that . is that it 是什么句式 it is obvious that 造句