O1签证对EB1A申请有用吗? 有人建议把O1签证也列在EB1A petition letter里面，这个有用吗？=> Yes, it will be helpful to mention it in your petition cover letter.
An individual previously approved as an O-1 nonimmigrant in the fields of science, education, business, or athletics may be successful in petitioning for EB1-EA classification, but the individual also will have to show substantial, prospective benefit to the U.S.
An individual cannot solely rely on the argument that an O-1 petition was approved. Each petition must stand on its own merit. It is very important for the EB1-EA petition to clearly show a benefit to the U.S. and demonstrate that the individual has risen to the very top of the field.
See http://www.greencardapply.com/o1visa/o1visa_advantage.htm
http://www.greencardapply.com
http://www.greencardfamily.com
