Quick links to the other verb types:
Click directly on the Go(5)-dan verb type you want to look up:

Irregular Verbs
- the ones that don't behave as you'd expect -

These are the four irregular verbs we need to know for NCEA.
​Click on the verb you want to know about:
​​くる（来る）- come
​Irregular ichi-dan type verb​
する - do​
Irregular ichi-dan type verb
​いく（行く）- go
​Irregular go-dan type verb
​​ある - there is/are
​​Irregular go-dan type verb​

くる（来る）- come
Ichi(1)-dan, irregular
TE Form
く changes to き.
Then, take off the る and replace with て
  • くる → きて
Verb Stem
く changes to き.
Then, drop the る 
  • くる → き
Alternatively, if you already know the -masu form, just drop the -masu and what you have left is the verb stem.
​きます→き
Plain Form
Non-past, positive (aka dictionary form):
  • くる - comes / will come
Non-past, negative:
  • こない - doesn't come / won't come
Past, positive:
  • きた - came
Past, negative:
  • こなかった - didn't come
Present continuous, non-past, positive:
  • きて いる - is/am/are coming
Present continuous, non-past, negative:
  • きて いない - is/am/are not coming
Potential (can):
  • こられる - can come
Year 13
Volitional (let's):
  • こよう - let's come
Not needed for NCEA, but handy to know.
-ます (masu) Form (Polite Form)
Non-past, positive:
  • きます - comes / will come
Non-past, negative:
  • きません - doesn't come/ won't come
Past, positive:
  • きました - came
Past, negative:
  • きません でした - didn't come
Present continuous, non-past, positive:
  • きて います - is/am/are coming
Present continuous, non-past, negative:
  • きて いません - is/am/are not coming
Potential (can):
  • こられます - can come
Year 13
Volitional (let's):
  • きましょう - let's come

する - do
Ichi(1)-dan, irregular
TE Form
  • する → して
Verb Stem
  • する → し
Plain Form
Non-past, positive (aka dictionary form):
  • する - does / will do
Non-past, negative:
  • しない - doesn't do/ won't do
For everything apart from the plain form (non-past, positive), the す in する becomes し. Other than that, this verb is pretty regular. Just note that there's no potential form. Instead, we use できる.
Past, positive:
  • した - did
Past, negative:
  • しなかった - didn't do
Potential (can):
  • できる - is able to / can​
Volitional (let's):
  • しよう - let's do
Not needed for NCEA, but handy to know.
-ます (masu) Form (Polite Form)
Non-past, positive:
  • します - does / will do
Non-past, negative:
  • しません - doesn't do / won't do
Potential (can):
  • できます - is able to / can
Volitional (let's):
  • しましょう - let's do

いく（行く）- to go
Go(5)-dan, irregular in the TE form only.
TE Form
  • いく → いって

ある - there is/there are; have (something) - for inanimate objects
Go(5)-dan, irregular in the plain negative forms (non-past and past) only.
Non-past, positive (aka dictionary form):
  • ある - there is / there will be
Non-past, negative:
  • ない - there isn't / there won't be
Past, positive:
  • あった - there was
Past, negative:
  • なかった - there wasn't
Also, as ある means "there is/are", it is not used in the continuous tenses.