Verb tense questions

[CommanderJo]

Hi there, im new to the na'vi community but i've been learning a lot about the language. im currently in the verb tense
and im a little confuse about the past,immediate past and all the other tense. The thing that confuses me is this...

ex: I sang a song.

would i be correct to assume that without further information to this sentense, it could be translate as follow:
- Oel tìrolit ramol     
- Oel tìrolit rìmol
- Oel tìrolit rolol

Could you explain the difference between -ol-   completed task  and the past tense... because
in my head, something in the past...at least the long past is already a completed task...

[wm.annis]

would i be correct to assume that without further information to this sentense, it could be translate as follow:
- Oel tìrolit ramol     
- Oel tìrolit rìmol
- Oel tìrolit rolol

Yes.

Could you explain the difference between -ol-   completed task

This infix isn't really about completion — that's the English perfect tense.  The ‹ol› infix is a perfective, a somewhat different thing.  There are contexts where it can be used to imply completion, but that is not its fundamental sense.  There's an introduction here: http://forum.learnnavi.org/syntax-grammar/na'vi-linguistics-tense-and-aspect/.

[Ftiafpi]

And some great examples of perfective and imperfective in English: http://forum.learnnavi.org/intermediate/pfv-and-ipfv-in-english/

[CommanderJo]

thx a lot, a look foward to start writing in na'vi in a while!