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问题 解答题

一块长方形地，长是17.6米，是宽的2.2倍．这块长方形地的面积是多少平方米？

答案

17.6×（17.6÷2.2），

=17.6×8，

=140.8（平方米）；

答：块长方形地的面积是140.8平方米．

问答题

计算线积分

，其中L为从点A(-π，0)沿曲线y=sinx到点B(π，0)的弧段．
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单项选择题

Crops can be traded on the futures market before they are harvested. If a poor corn harvest is predicted, prices of corn futures rise; if a bountiful corn harvest is predicted, prices of corn futures fall. This morning meteorologists are predicting much-needed rain for the corn-growing region starting tomorrow. Therefore, since adequate moisture is essential for the current crop’s survival, prices of corn futures will fall sharply today.
Which of the following, if true, most weakens the argument above

A．Corn that does not receive adequate moisture during its critical pollination stage will not produce a bountiful harvest.

B．Futures prices for corn have been fluctuating more dramatically this season than last season.

C．The rain that meteorologists predicted for tomorrow is expected to extend well beyond the corn-growing region.

D．Agriculture experts announced today that a disease that has devastated some of the corn crop will spread widely before the end of the growing season.

E．(E) Most people who trade in corn futures rarely take physical possession of the corn they trade.
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