The arm bones of women who lived 7,000 years ago show a surprising level of strength--even higher th

28. C    29. A    30. C    31. D
【解析】
【分析】
本文是说明文。根据一项针对7000年前生活的女性骨骼研究显示，这些史前女性的手臂力量大于如今的女性。
【28题详解】
细节理解题。根据第一段The finding suggests a revision of history- the everyday lives of prehistoric women were filled with hard labor, rather than just sitting at home doing lighter tasks while the men struggled and fought for life.得知研究发现史前女性所从事的体力劳动和男性一样艰苦。故选C。
【29题详解】
推理判断题。根据第三段Previous studies only compared female bones to contemporary male bones, the researchers said-and that's a problem,得知问题是：此前的研究只是将女性骨骼和男性骨骼对比，但这种方法很可能低估了女性的工作强度，可以推断出缺乏比较。故选A。
【30题详解】
词义猜测题。根据because the response of male bones to stress and change is much bigger than that of women.得知男性骨骼相对于女性骨骼来说对压力作出的反应更明显，前后在对比the response of bones to stress。故选C。
【31题详解】
推理判断题。根据最后一段Prehistoric women, the researchers found, had arm strength 11-16 percent stronger than those of modern rowers, and 30 percent stronger than those of non-athletes.得知研究发现史前女性比现代女性更强壮。故选D。
【点睛】小题4属于推理判断题中的：根据事实细节，推断合理信息。推理题要求在理解原文表面文字信息的基础上，作出一定判断和推论，从而得到文章的隐含意义和深层意义。推理题所涉及的内容可能是文中某一句话，也可是某几句话，但做题的指导思想都是以文字信息为依据，既不能做出在原文中找不到文字根据的推理，也不能根据表面文字信息做多步推理。也就是说，要做到判断有据, 推论有理, 忠实原文。切忌用自己的观点代替作者的本意，切忌片面思考，得出片面结论。
答案定位：根据Prehistoric women, the researchers found, had arm strength 11-16 percent stronger than those of modern rowers, and 30 percent stronger than those of non-athletes.得知研究发现史前女性比现代女性更强壮。
推理关系：题干What can we learn from the last paragraph?文章内容Prehistoric women, the researchers found, had arm strength 11-16 percent stronger than those of modern rowers, and 30 percent stronger than those of non-athletes.
答案： D选项Prehistoric women are stronger than contemporary females