回复：485 rfe-how confirm I intend to---

But that can only prove I am able to continously contribute to this area. How can I prove I intend to work on the area ?

-Your recent publications, meeting abtracts, etc. and your supervisor's letter are enough to prove "that you intend to carry out the terms and conditions of the underlying From I-140 visa petition".

Do I need to write something to show my intention in the coverletter?

-Not necessary, but not hurt you to say something about that in a few sentences.

Can you teach me what to do?

-Just say something about your current job and will continue to do it in your whole career, etc. Anyway, not so important.