Tense is relative time (had happened, happened, happens, is happening, will have happened, will happen, will be going to happen after, and I'm sure one could come up with even more convoluted intuitively usable tenses in english), the thing that modifies the object/subject relationship in a sentence is the voice ("subject does [to object]" vs "subject is done to by agent" in english, but theoretically a language could change that up more I just don't know of any examples off hand).
Tense is relative time (had happened, happened, happens, is happening, will have happened, will happen, will be going to happen after, and I'm sure one could come up with even more convoluted intuitively usable tenses in english), the thing that modifies the object/subject relationship in a sentence is the voice ("subject does [to object]" vs "subject is done to by agent" in english, but theoretically a language could change that up more I just don't know of any examples off hand).