each of us是單數還是複數

例句：

I believe that each of us can contribute to the future of the world.

我相信我們每一個人都能夠對世界的未來有所貢獻。

We must,each of us,prevail upon our congressman to act.

我們每一個人都必須説服我們各自的'國會議員採取行動。

A guard came and took our names and noted where each of us was sitting.

一名警衞來記了我們的名字，還記下了我們每個人的座位。