在英语毕业论文答辩时，如果答不上来，怎么用英语说“这个问题，我还没有详细研究，请老师给予指点”？

Dear Sir/Madam,
I haven't researched this issue(point) in detail, would you please give me any directions? Thanks

I haven't thought about it carefully. Would you please give me some suggestions?

答辩的时候，我从来没这么说过。

不知道，我就说 i don't know.

然后，把为什么论文没有涵盖这个问题点再解释一下。

I haven't done detailed reserch on that issue, would you give some comments on it please?

I'm sorry that I didn't do any further research on this issue. Would you pls give me some ideas?

I have't got into this problem,I hope I can get something about it from teachers.