take part in、join in 和 attend，它们都有“参与，参加”的意思，用法区别如下：
1)join 表示"加入党派，组织、社团、俱乐部"等。
如：join the Party/Youth League……
His brother joined the army a year ago.
2)join in 表示"参加正在进行的活动"。参加游戏/讨论/谈话/一起散步/一起讨论。
如：join in a game ……
They are playing football， do you want to join in?
3)take part in 表示"参加会议、活动"，侧重说明主语参加并发挥一定作用。
如:take (an active)part in a party/school activities
The teacher encourages all children to take part in the school dance competition.老师鼓励所有的小朋友都参加学校的舞蹈比赛。
4)attend 表示"出席、参加会议、仪式、婚礼、葬礼等
如：attend a meeting/a sports meeting……
Mike didn't attend Lily's wedding.
Jake attended the court hearing last week.
