She tugged at his sleeve to get his attention.她拽了拽他的袖子引起他的注意。A wry smile tugged at the corner of his mouth.他的嘴角带一丝苦笑.The sight of the poor child crying tugged at my heartstrings.看到那小孩啼哭,我真心疼....
According to the characteristics of element abiochemistry, the author concludes some methods of teaching on it.针对元素无机化学教学内容的特点, 介绍了在组织元素无机化学的教学过程中的几点做法和体会....