设y=f(x)存点x处的切线斜率为2x+e-x，则过点(0，1)的曲线方程为
A. x2-e-x+2
B. x2+e-x+2
C. x2-e-x-2
D. x2+e-x-2
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All of the following are mentioned in Paragraph 4 as results of the introduction of the heavy plow EXCEPT
A. a rise in trade with the peoples of Eastern Europe.
B. a change in the standard shape of farm fields.
C. an increase in the communal undertakings of farmers.
D. a decrease in the time needed to prepare fields for planting.
According to Paragraph 5, what was the benefit of using horses to plow fields instead of oxen？
A. They required less food during the day.
B. They pulled heavier loads.
C. Their necks were less susceptible to strain.
D. They worked faster and longer.
已知函数f(x)具有任意阶导数，且fˊ(x)＝[f(x)]2，则当n为大于2的正整数时，f(x)的n阶导数，则f(n)(x)为()．
A. n![f(x)]n＋1
B. n[f(x)]n＋1
C. [f(x)]2n
D. n![f(x)]2n
What can be inferred from Paragraph 6 about the pheromones of female snakes？
A. They are produced year round.
B. They are species specific.
C. They are only detectable by male snakes.
D. They are the strongest chemical odors.
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