each of us是单数还是复数

　　例句：

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

　　我相信我们每一个人都能够对世界的未来有所贡献。

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

　　我们每一个人都必须说服我们各自的'国会议员采取行动。

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

　　一名警卫来记了我们的名字，还记下了我们每个人的座位。