A. About 100 years ago. B. In this century. C. At the beginning of the 19th century. D. In 1798. 参考答案:A 答案解析:事实细节题。在本文第一段中的第二个句子中可找出本题答案。By their tremendous heroism, men such as Shckleton,Scott,and Amundsen ca
第32题: [单项选择]空气的垂直运动包括() A. 上升运动,下沉运动 B. 平流风 C. C.B都对 D. D.B都错 参考答案:A