[单项选择]In North America, the Nebraska culture that succeeded the Woodland culture about A.D 1300 pioneered in------to become the area's chief economic activity, agriculture.
A. it was B. which was C. what was D. was
参考答案:
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第1题: [多项选择]地表水取水构筑物位置的选择，应根据( )等基本要求，通过技术经济比较确定。 A. 位于水质较好的地带 B. 靠近主流，有足够的水深，有稳定的河床及岸边，有良好的工程地质条件 C. 尽量靠近主要用水地区 D. 供生活饮用水的地表水取水构筑物应位于城镇和工业企业上游的清洁河段 参考答案:A,B,C,D 答案解析:参见《室外给水设计规范》(GB 50013—2006)第5.3.1条。
第28题: [单项选择]Halley made his discovery ______. A. by doing experiments B. by means of his own careful observation C. by using the work of other scientists D. by chance 参考答案:C 答案解析:本题属对细节信息的深层理解推断题。其关键词是made．．，discovery。Halley的discovery是基于对comets that had been observed by scientis
