And that's a sweater that buttons down.

那是一件扣子扣下来的毛衣。

To sweater that buttons down, typically it doesn't have a collar, right?

扣子扣下来的毛衣，通常没有领子，对吗？

Two buttons down the front, three on each sleeve.

正面两颗纽扣，袖子上有三颗。

A " dress shirt" is a nice men's shirt, something that you would wear for work in an office, something a little more formal, usually with buttons down the front.

“正装衬衫” 是一件漂亮的男式衬衫，是您在办公室工作时会穿的东西， 稍微正式一些， 通常前面有纽扣。