Another
Japanese verb base with wide usage, base 7 is sometimes known as the TA-form.
Among other things, this base can be used as a past tense form in
informal speech.
It is also used for
conditionals, discussion of past
experiences, etc.
Phonologically, Base 7 is exactly the same as Base 6, except that the final vowel is
-a rather than -e. To form Godan verbs into Base 7, use the following
pattern:
Again, note the sound change from
-ta to
-da when demanded by euphony.
For Ichidan verbs, subtract -ru and add -ta.
As for irregulars, suru becomes shita, and kuru becomes kita.
Iku is irregular in Base 7, and becomes itta. Desu becomes datta in
Base 7. This is important for many verb endings.
With no ending, a verb in Base 7 expresses the informal (plain) past tense (compare with
Base 2 + -mashita):
Kinoo mainichi terebi o mita.
Yesterday, I watched TV all day. (to a friend, family member)
Kinoo mainichi terebi o mimashita.
Yesterday, I watched TV all day. (to people not known as well)
Common endings for Base 7 include -ra, which expresses a simple conditional:
O-tomodachi ga ima koko ni kitara, doo shimasu ka.
What would you do if your friend came back now?
Another common ending adds koto ga aru, which expresses an experience or time
of having done something, as follows:
Watashi wa mekishiko e itta koto ga arimasu.
I have been to Mexico.
Note that aru in the previous ending had to be properly inflected. This applies for
pretty much any Japanese verb ending that isn't strictly particular, like the ending
-ri, which is used to compose a non-inclusive list of verbs. The tense of the list
is expressed by the final verb, which is usually a form of suru. "Non-inclusive list" is
a pseudogrammatical term for the notion "...and things like that", in case you were
wondering:
Watashi wa kaetta atoo de, pizza o tabetari, biiru o nondari, ongaku o kiitari shimasu.
When I get home, I eat pizza, drink beer, listen to music, and things like that.