swim team,swimming teamI'm on the swim team.我在游泳队.为什么不能用swimming team呢?就像driving licence一样,动名词+名词.

在这里swim 做adj.（形容词）
意思是Of,relating to,or used for swimming:
游泳的：属于、关于或用于游泳的：
例如：a swim mask.游泳面罩
而swimming是名词,如 swimming is interesing 游泳很有趣
Swimming is a good sport in summer.等
这个用法有些偏,其实英语里有许多都是习惯搭配用法,就像为什么英语中有is am are was were 而在中文中找不到准确对应的词一样,语言学习重在多积累哈,祝学习进步······