I came from China in 1998 on F-1 visa, graduated in 2005 and became a professor in a college, switched to H1B in 2006. I had claimed the $5000 tax-treaty benefit until and including year 2006. I paid tax and filed tax return as a regular resident alien for tax years 2007 and 2008. According to the US-China tax treaty article 19, shown below, it seems that all my 2007 and 2008 income should have been tax exempt. Am I right ? Sounds too good to be true. Can I file tax amendment for those two years and get all my tax back?

ARTICLE 19
(Teachers, Professors and Researchers)
An individual who is, or immediately before visiting a Contracting State was, a resident of the other Contracting State and is temporarily present in the first-mentioned Contracting State for the primary purpose of teaching, giving lectures or conducting research at a university, college, school or other accredited educational institution or scientific research institution in the first mentioned Contracting State shall be exempt from tax in the first mentioned Contracting State for a period not exceeding three years in the aggregate in respect of remuneration for such teaching, lectures or research.

Another question, I was a full-time student for the full year 2009 while teaching full-time on H1B for the first 6 months of 2009, and I did an internship for a company. Can I claim the $5000 tax treaty benefit based on article 20(c) and the Saving Clause exception for Chinese students ?

Thank you very much.

For tax treaty article 19 you must be in the U.S. on J-1 visa as teacher, researcher or professor. You are on H1-B work visa. With this visa you do not get tax treaty benefits. Your U.S. Tax Return: The U.S. Visas