如果上述情况确实存在,并且吸烟确实增加生畸形儿的危险,那么,研究结果的相对危险度与真实的相对危险度相比是
A. 相同
B. 高估了
C. 低估了
D. 颠倒了
E. 不能确定
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[A] cured [B]changed [C]improved[D] saved
___________the weather was fine,I opened all the windows. [A]For[B]Becauseof[C]Nowthat[D]Sincethat
What can we learn from thepassage?[A]Peoplekeep dogs mostly for companionship now. [B]Mostpeople in the West still keep dogs for protection. [C]Peoplekeep dogs because they love animals.