Chapter 7- how global markets work imports- goods and services we buy from other countries exports- goods and services we sell to people in other countries. International trade today: united states is the world"s largest international trader, germany and china rank second and third, lag by a large margin in 2008 canadian exports were billion, imports were billion. What drives international trade? comparative advantage is the fundamental force that drives international trade national comparative advantage as a situation in which a nation countries gain from international trade. Winners, losers and the net gain from trade international trade has winners but it also has losers. International trade restrictions four sets of tolls to influence international trade and protect domestic industries from foreign competition. The effects of a tariff expands surplus shrinks surplus from imports and total surplus quantity surplus shrinks expands surplus from exports: with a tariff set at per shirt, changes occur.