单项选择题
A.空中运输业是一种以雇佣飞机来输送乘客,货物和信件的一种商业贸易。 B.空运业是商业的一个领域,它就是用飞机运送乘客,货物及邮件。 C.空运业务是贸易领域的一项业务,它可以用飞机来载人,运货物和邮件。 D.航空运输业是一个商业领域,在这个领域中用飞机运送旅客,货物和邮件。
A.do not pay their workers sufficient wages B.arc hurt by a trade imbalance C.import labor and materials from overseas D.provide a strong industrial base that prevents a trade deficit
A.Several worldwide economic problems. B.The causes and consequences of trade deficit. C.Lack of resources in underdeveloped countries. D.The value of exports against imports.