一位同学在探究“充水玻璃管中气泡的运动规律”时用到的测量工具有 ____和 ____，为便于测量，应使气泡在管内运动得较 ____（快/慢）．下表是他所记录的数据：

由表可知，该气泡在2s内的速度 ____（填“等于”或“不等于”）4s内的速度，每1s内通过的路程 ____（填“相等”或“不相等”）．

12×5＝____       120×5＝____

120×50＝____     1200×50＝____

50×1200＝____    12×5000＝____

    Davidson Black was a____(Canada) doctor who organized the excavation that led to the discovery of the bones in the Zhoukoudian____(cave) near Beijing. He was a specialist in the study of bones____it was his ambition to find and identify bones of early humans. His university was aware____the significance of his work. At first they gave him ample time to do his research, but____(late) they realized he was prepared to pursue it regardless of his students' needs and his____(teach) career, so they forbade him ____(travel) there any more. It was his assistant, Pei Wenzhong____made the discovery of these primitive bones and____(sharpen) tools. Davidson Black knew that his success was almost ____(entire) due to his assistant's systematic hard work.