I have been suffering from the cancer for tow years 中的suffer为什么用ing形式

I have been selling I have been trying I have ever been I too have been I have been to. I have been I have been in. I have been there,have been 是have been in还是have been to的缩写? i have always been there i have never been there I HAVE NEVER BEEN,能否说I never have been I have been so serious I have been so serious I-have-been-at-home I have always been you I have been loving you I have been a person . I have never been away! I have been wet through because i have been died.