Kate with his friends go to see a film .Kate with his friends is go to see a film.

问题描述:

Kate with his friends go to see a film .Kate with his friends is go to see a film.

不加 go 已经是动词了 不需要Be动词了
同时 应该用goes 三人称单数
因为with是就远原则
也就是谓语的单复数形式 根据最前面那个主语来定
在句中 就是根据KATE来定
希望能够帮到楼主