A country has an absolute advantage in the production of a product when it is more efficient than any other country in producing it.
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According to Ricardo's theory of comparative advantage, countries shall not produce a good, even if they have an absolute advantage in its production, if they do not produce it efficiently.
A. 对
B. 错
测血压时，松开气门使汞柱缓慢下降，听到第一声搏动音时，袖带内压力
A. 大于心脏收缩压
B. 等于心脏收缩压
C. 小于心脏收缩压
D. 等于心脏舒张压
下列因素除哪项外，可使血压值升高
A. 寒冷刺激
B. 高热环境
C. 兴奋
D. 精神紧张
中心静脉压的测定主要反映
A. 外周阻力的大小
B. 心率快慢
C. 大动脉管壁的顺应性大小
D. 回心血量多少
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