"和...在一起" 的英文表达有多种可能，具体取决于所描述的上下文。常见的表达方式有：

"Together with" 或 "Along with"：
例句：
I'm going to the park together with my friends.
我和朋友一起去公园。
She came along with her brother.
她和她的兄弟一起来了。
"In the company of"：
例句：
I'm happy to be in the company of good friends.
我很高兴和好朋友在一起。
She enjoys reading in the company of her cat.
她喜欢在猫的陪伴下阅读。
"With"：
例句：
I'm going to the movies with my girlfriend.
我和女友一起去电影院。
They're having dinner with their parents.
他们和父母一起吃晚餐。

这些表达方式均为英语中常用的表示“和...在一起”的说法。