英语翻译已经知道的三种是1.He has been in the army for 5 years.2.He has b

4.He became an armyman 5 years ago.
5.He has been an armyman since 5 years ago.
6.He has been an armyman for 5 years.
【看到了补充】
如果要难一点的话,可以说：
7.He has been on active service for 5 years.
8.He became a military man 5 years ago.