1. join in 加入；参加，侧重于参加某个团体或者活动（活动）例句：We're going to play football. Do you want to join in 我们去踢足球，你来不来？May I join in the discussion 我可以参加讨论吗 2. cometo、come to后接名词、数词、代词或不接任何词:1）谈到,涉及到:When it comes to physics,he is a complete stranger.谈到物理,他完全是个外行。

The school has very good teachers, but when it comes to buildings, the school is poor.这个学校有好老师,但是从校舍来看很贫穷。

2）表示“合计，总共”，同amount to.—How much does the bill come to？帐单上共多少钱？3)表示“开始被„所认识，被„所记起。”突然想起(无被动式)—In a flash, the truth came to him.突然间，他明白了真相。—I was on my way when it suddenly came to me that I had not hung out my washing. 我已经上了路，突然想到洗的东西没有晾出去。—Suddenly, the words of the song came to me.突然间,我想起这首歌的歌词来。

4）发生(在某人身上),降临于(某人):—Happiness will come to you as long as you are after it.只要你追寻它,幸福会降临于你。

5）恢复知觉,苏醒过来:—After three hours in the hospital bed, he began to come to.躺在医院床上三个小时后,他开始苏醒过来。

6)come to 后接地点时 表示到某地Please remember to come to the classroom to take your book.记得要去教室取你的书