上游充通大学 材料科学与工程学院 School of Materials Science and Engineering.SITU 1896 1920 1987 2006 Teamwork The lead goose rotates back when it gets tired and another goose takes over. 1日日日 工程学导论-李军（材料B楼308）1896 1920 1987 2006 工程学导论-李军（材料B楼308） The lead goose rotates back when it gets tired and another goose takes over. Teamwork