甩动和跺脚这两种力的结合是导致鞋带突然松开的原因。 But not when they are, say, sitting on the edge of a table and swinging their legs. 研究人员注意到,鞋带结经常在人们走路时散开。 Laces also stay tight when marching in place with no forward motion. 但是当人们坐在桌边晃腿时,鞋带却不会松...
科学美国人60秒听力练习:鞋带为什么会松 科学美国人60秒英文文本 This is Scientific American — 60-Second Science. I'm Karen Hopkin. This will just take a minute. You're strolling down the street or maybe hauling that load of laundry down a flight of stairs when all of a sudden. [sound fx...
科学美国人60秒:鞋带为什么会松MP3音频下载,你在街上漫步,或是搬着一大堆衣服下楼,这时突然……(音效)你的鞋带松了。