this is a question difficult to answer对吗

this is a question difficult to answer对吗 This question is very difficult to answer改为同义句 This question is very difficult to answer的同义句 This question is difficult to answer.和This question is diffi this question is not difficult ------- (answer) i found ,difficult to answer this question it is difficult to answer this question.为什么在answer前面加to the question is difficult to answer What is the sky This question is very difficult to answer ,i To answer this question is difficult to me（同义句） I think it is difficult for me to answer this question(改为简单句 I think it difficult to answer this question 为什么可以it 不加is?