回複：回複：NIW approved

It took me a long time to write the cover letter. What you are writing is to let the officer believe you have already made and will make contributions to the US economy, environment, .... The officer may have no idea about your research field. It totally depends on what you say. Don't say too much how great you contributed to the scientific community, although it is also important. Of course, this point is only for NIW case. I am not sure I am right. Good luck to you.