If country A has a comparative advantage in producing shoes, then________________________.（ ）. A: other countries will never produce shoes if trade is allowed B: it can produce shoes at lower opportunity costs than other countries can C: it has more factors of production used in the production of shoes relative to other countries D: it can produce shoes using more resources than other countries can

Because of substantial economies of scale, the _____ theory argues that trade can increase the variety of goods available to consumers. A: absolute advantage B: technological gap C: new trade D: factor endowments

( ) is established based on the principles of ecology and economics. Besides, the modern scientific and technological achievements, modern management means, effective experience of traditional agriculture are all combined, so it can be used to higher ecological and economic benefits, social benefits. A: Circular Agriculture B: Intelligent Agriculture C: Ecological Agriculture D: Green Agriculture

Which of the the following statements is true true ? ( ) A: “Two countries can achieve gains from trade even if one of the<br/>countries has an absolute advantage in the production of all goods.” B: “Certain very talented people have a comparative advantage in<br/>everything they do.” C: “If a certain trade is good for one person, it can’t be<br/>good for the other one.” D: “If trade is good for a country, it must be good for everyone in the country.”

We are calling for an environmentally-friendly system where the waste and rubbish can be ______ of using the principles of ecology. A: informed B: disposed C: suspected D: approved