Would you please help me to answer a question about tax treaty for scholars from China: the treat exemption is avaliable only for compensation received during a maxium aggregate period of three years. How to caculate the three years? Is it 3 calendar years from date of arrival in the U.S.? e.g. if I arrived in the US on 7/1/02, the benefit should be end 6/30/05 or 12/31/04? Thank you so much.