I have a lot of questions about english,can you help me?

A: when did you came here?
B: at last week （去掉at）
I want do best friend with you
I want going to finish my work
这两句有问题
want 后面要加to do,最高级前要加the,这样改：
I want to be the best friends with you.
I want to go to finish my work .
希望能帮到你,祝你开心,进步^_^有问题给我留言哈!