presentation by Qijiao Chen https://padlet.com/chenqijiao0503/tp62wdwt8xei chenqijiao,lizijie,liwenhua,xuerong en-us 2017-07-25 20:04:44 UTC 2025-12-29 19:38:19 UTC hello@padlet.com picture chenqijiao0503 https://padlet.com/chenqijiao0503/tp62wdwt8xei/wish/179766205 2017-07-31 12:57:13 UTC https://padlet.com/chenqijiao0503/tp62wdwt8xei/wish/179766205