On the night of May 7, 1942, a plane
took off from an Air Force base in England to stop German fighters over the
English Channel. Pilot of the plane was Captain Thomas Nash. Looking eastward,
Nash saw twelve orange lights in a row, moving at a fantastic rate of speed. As
a sophisticated flyer, he had never seen anything like them. Thinking that they
might be a new German weapon, he decided to chase them. But when he Swung the
plane around and headed directly for the lights, they vanished. Captain Nash may have been the first to see such orange lights but he wasn’t the last. His experience was repeated several times by pilots during World War Ⅱ in Europe and the Far East. What were they No one knows for sure, but there is an interesting theory to explain them. According to this theory, the orange lights are space a A. from the ground B. from a rocket ship C. during World War Ⅰ D. during World War Ⅱ [单项选择]中心静脉插管感染最常见的致病菌是
A. 需氧革兰阳性球菌 B. 真菌 C. 厌氧菌 D. 需氧革兰阴性杆菌 E. 破伤风芽胞杆菌 [单选题]连续出现或长期出现爆炸性粉尘的环境区域属于()区。
A.10 B.0 C.21 [单项选择]正常男性精囊腺产生的液体pH值属于
A. 强酸性 B. 强碱性 C. 中性 D. 弱碱性 E. 弱酸性 [判断题]空调系统螺杆机应检查压缩机制冷剂液位正常
A.正确 B.错误 [单选题]下⾯不是锅炉主要技术、经济、环保性指标的是
A.锅炉容量 B.锅炉效率 C.环保性能 D.锅炉体积 [单选题]预警通知单应提前发布,原则上在作业实施前不少于()日发布。
A.3 B.5 C.7 D.10 我来回答: 提交
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