join join in take part in attend区别是用法不同、使用范围不同。join指加入某个党派，团体组织等，join in多指参加小规模的活动如球赛、游戏等，take part in 指参加会议或群众性活动等，attend是正式用语，及物动词，指参加会议、婚礼等。

例句：She joined the Young Pioneers.她加入了少先队.He'll join us in singing the song.他将和我们一道唱歌.Come along,and join in the ball game.快,来参加球赛.We often take part in physical labor.我们经常参加体力劳动.I attended his lecture.我听了他的讲课。