第6题: [单项选择]That boys suffer more from air pollution can possibly be justified by the fact that A. the male have larger bones than the female. B. women can manufacture blood more efficiently than men. C. men usually breathe more deeply than women. D. women breathe as often as men. 参考答案:C 答案解析:[解析]从文章第一段最后一句可知：But men breathe more deeply and this exposes them to another risk．They draw more of
第7题: [单项选择]牙体长轴是 A. 通过牙体中心的一条假想轴 B. 通过牙冠与牙根中心的一条假想轴 C. 通过牙冠中心的一条假想轴 D. 通过牙根中心的一条假想轴 E. 贯穿冠、根的一条假想轴 参考答案:A 答案解析:牙体长轴是通过牙体中心的一条假想轴。
