attend、join、participate与take part in这些动词或词组均含“参加，加入”之意。
attend ：侧重参加或出席会议或学术活动等。
The meeting was attended by 90% of shareholders.
90%的股东出席了会议。
to attend a wedding/funeral
参加婚礼 / 葬礼
We'd like as many people as possible to attend.
我们希望出席的人越多越好。
join ：普通用词，指加入党派、团体或游戏活动等。
I've joined an aerobics class.
我参加了有氧健身班。
She joined the company three months ago.
她三个月前进了这家公司。
(figurative) to join the ranks of the unemployed
加入失业大军
participate ：正式用词，特指参加团体活动，暗示以一个积极的角色参加。
We encourage students to participate fully in the running of the college.
我们鼓励学生全面参与学院的运作。
He planned to participate in the demonstration, but then he got cold feet.
他打算参加示威，但后来临阵退缩了。
take part in ：侧重参加某项群众性、集体性的事业、工作或活动，突出参加者在其中发挥一定的作用。
If you want knowledge, you must take part in the practice of changing reality.
你要有知识，你就得参加变革现实的实践。
Amongst those who have travelled furthest to take part in the Festival are a group from Northern Ireland.
在那些不远万里赶来参加节日活动的人中有一群来自北爱尔兰。