2. ... Except as provided in paragraph 2 of Article 8, paragraph 2 of Article 17, and Articles 18, 19, 20, 22, 23, 24 and 26 of this Agreement, the United States may tax its residents (as determined under Article 4).
查ISR官网The Green Card Test and the Substantial Presence Test：五年在美不需要连续，只要累计calendar years。
the 5 calendar years need not be consecutive; and once a cumulative total of 5 calendar years is reached during the student’s lifetime after 1984 he may never be an exempt individual as a student ever again during his lifetime;