根据比较优势定律，应该根据以下哪项内容来确定由哪个国家生产某一具体产品
A．机会成本。
B．利润率。
C．经济订货量。
D．关税。
参考答案：A
解析：
A．正确。各个国家各自的机会成本决定了它们将要生产哪种产品。
B．不正确，因为利润率并不影响该决策。
C．不正确，经济订货量决定了最优存货水平。
D．不正确，只有每个国家生产各自的产品时，关税才能发挥作用。
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| Many objects that people use each day started with a simple idea. These objects have often changed the way we 1 . Some help us to do a job more 2 . Others fill a need or solve a problem. In 1858, Lipman had such an 3 . He took out a pencil, a piece of paper, 4 an eraser. Then he began to write. Sometimes he needed to 5 a word. Each time he had to search under his books and papers to 6 the eraser." I wish my eraser would stay in one 7 !" he said. Then Lipman had his simple idea. He 8 a groove (凹槽) in one end of the pencil. He glued (粘牢) the eraser into the groove. Lipman had solved his problem. Later he thought that others might like to have such a pencil. So he sold his 9 . Some pencils with erasers were 10 . His design earned $ 100000. | ||||
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