求international economics和英文高手

總共有9題關於international economics的問題
請幫我看看是TRUE OR FALSE, AND WHY?
1) A country cannot have a comparative advantage in the production of all goods.
2) The Leontief Paradox refers to the lack of validity of the Ricardian theory of trade
3) Porter's Diamond is useful to analyze national competitive advantage.
4) A trade tariff imposed by a big country government generates gains for the consumers of that country.
5) The existence of high transport costs is a motivation for horizontal Foreign Direct Investment.
6) International trade in similar goods in explained by the principle of comparative advantage.
7) A vertical FDI might solve an "hold-up" problem
8) The most favoured nation clause doesn't apply to non competitive countries.
9) The difference between a Free Trade Area and a Custom Union is that the former creates an area where free trade is allowed and the second, on the contrary, introduces barriers to trade.