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【单选题】
The decline of Atlantic seaports was a result of the inland waterway system in the United States.A.
正确
B.
错误
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皮皮学刷刷变学霸
举一反三
【简答题】可吸入粒子指直径 ()的颗粒物
【简答题】请根据肌肉收缩张力与速度的关系原理分析力量型、速度力量型、爆发力型、力量速度型和速度型运动项目力量训练的差异。
【单选题】Walt considers x and y to be perfect substitutes. They originally cost 10 and 9 respectively. His income is 720. One day the price of x drops to 8. Which of the following is true?
A.
The income effect increases the quantity of y by 90．
B.
The substitution effect increases the quantity of y by 80.
C.
The substitution effect increases the quantity of x by 90.
D.
The income effect increases the quantity of x by 80.