"Masu" verb form vs "Imperfective" verb form


I'm trying to put together a chart for myself, to learn the rules for verb
conjugation. However, I'm confused at the "Imperfective" and "Perfective" verb
conjugations - aren't they just informal versions of the "Masu" verb forms? To
my understanding, the "masu" verb forms are polite ways to say something is
either happening or will happen - just like the "Imperfective" verbs(Which
appear to just be the dictionary forms?)

  * For example, "Tabemasu" vs "Taberu" - both mean that something is either being eaten or will be eaten.

Likewise, the "mashita" verb forms indicate that something has already
happened - just like the "perfective" verb forms.

  * For example, "Tabemashita" vs "Tabeta" - both mean something has been eaten? 




> For example, "Tabemashita" vs "Tabeta" - both mean something has been eaten?

Yes. They do not differ in meaning, only usage.

Keep in mind there are some times when it's inappropriate to use たべた (
_tabeta_ ); typically these are in more formal (or less familiar) situations.
Conversely, there are times when it is inappropriate to use たべました (
_tabemashita_ ); typically these are in more familiar situations, among family
or friends, or in certain grammatical constructs. (This would also be the case
for _taberu_ and _tabemasu_ , and so on.)

If you want to read further on the topic, there's quite a bit of discussion
and help surrounding these constructs.

  * [WordReference forum](http://forum.wordreference.com/showthread.php?t=558671)
  * [Tae Kim's Guide to Japanese](http://www.guidetojapanese.org/learn/grammar/polite)
  * [About.com](http://japanese.about.com/library/weekly/aa031101b.htm)




> For example, "Tabemashita" vs "Tabeta" - both mean something has been eaten?

Yes. They do not differ in meaning, only usage.

Keep in mind there are some times when it's inappropriate to use たべた (
_tabeta_ ); typically these are in more formal (or less familiar) situations.
Conversely, there are times when it is inappropriate to use たべました (
_tabemashita_ ); typically these are in more familiar situations, among family
or friends, or in certain grammatical constructs. (This would also be the case
for _taberu_ and _tabemasu_ , and so on.)

If you want to read further on the topic, there's quite a bit of discussion
and help surrounding these constructs.

  * [WordReference forum](http://forum.wordreference.com/showthread.php?t=558671)
  * [Tae Kim's Guide to Japanese](http://www.guidetojapanese.org/learn/grammar/polite)
  * [About.com](http://japanese.about.com/library/weekly/aa031101b.htm)

