Chapter 5 1. According to classical trade theory, the difference of countries lead to IT the bigger the difference, the more trade possibility 2. However after 60s. the north-North Trade exceeded the“ North- South trade” 2006年版2006年版 Chapter 5 1. According to classical trade theory, the difference of countries lead to IT; the bigger the difference, the more trade possibility 2. However, after 60s, the “North-North Trade” exceeded the “North-South Trade