Verbs

There are two kinds of verbs in the Polish language, perfective and imperfective verbs.
You use the perfective verbs for completed or single actions, single actions in the future and actions which will be completed in the future.
You use the imperfective verbs for actions still in progress, extending over a longer time period, repeated and habitual actions.
Perfective verbs occur only in past tense, simple future and conditional tense.
Imperfective verbs occur in present tense, past tense, composite future and in the conditional tense.

Infinitive:
There are 15 different endings for infinitive verbs in Polish:
ać, ować, ywać, iwać, awać, ąć, nąć, eć, ieć, ić, yć, uć, ść, źś and c.
Some verbs have non-reflexive and reflexive forms, sometimes even with total different meanings.
Function:
    - for impersonal expressions
    - after modal auxiliaries
    - as object for an other verb
    - to express the English gerund
    - as complement for the verb "być" (to be)
    - in passive expressions with verbs (like: czuć, słychać, widać or znać)
    - as a object for an imperative expressions
    - official imperative expressions (without 'proszę')
    - polite imperative expressions (with 'proszę')
    - in noun clauses

Verb conjugation groups:
There are 4 main categories, and some of them do have sub-groups as well.
Only the verb być falls in non of these categories.
Conjugation 1: Nearly all verbs ending in ać (except of ować, ywać, iwać or awać). Mieć belong in it as well.
Conjugation 2: Some verbs ending in ieć belong into this category. The verb jeść belongs to here to.
Conjugation 3a: Verbs ending in awać, iwać, ować or ywać.
Conjugation 3b: Some verbs ending ać, eć, uć or yć.
Conjugation 3c: Verbs in ać, eć, eć, uc, yc and c.
Conjugation 3d: All verbs ending in nąć or ąć belong to this group.
Conjugation 3e: Verbs ending with ść (but not jeść) and źć.
Conjugation 4a: These verbs end in bić, mić, nić, pić or wić.
Conjugation 4b: Most verbs in ić, and a few ending oić, eić or ać.
Conjugation 4c: These usually end in yć and some verbs in eć as well. The verb stem ends usually with cz, szcz, ż, żdż or rz.

Reflexive verbs:
Reflexive verbs have the additionally reflexive pronoun się.
This pronoun stands after the 1st stressed word or close to the reflexive verb. Only in very short sentences it can be at the end.

Imperative:
Both, perfective and imperfective verbs, do have a imperative form. It is used to express 'do now' or 'do always' with imperfect verbs. And with perfective verbs to say 'do once in competition and in the future'.
Usually the imperative is used for negative commands. (do not...)
Formation:
Conjugation 1 + 2: Take the 4rd person plural and remove the ą of the future (imp) or present (per) tense- to get the form for the 2nd person singular. For the 1st person plural just add then my. And cie for the 2nd person singular.
Conjugation 3 + 4:
    a) usually remove the ending e, i or y from the 3rd person singular of the future (imp) or present (per) tense.
    b) verbs ending in cić, nić, sić, zić or dzić lost the iof the 3rd person singular form.
    c) the vowel o if often changed to ó
    d) verbs that end in a consonant cluster add ij or yj
    e) there are some irregular verbs:
        być - bądź
        brać - bierz
        dać - daj
        dawać - dawaj
        mieć - miej
        wysłać - wyślij
        wziąć - weź
    f) some verbs don't have a imperative form at all, these use the additionally word niech.
        boleć, brakować, jeździć, kosztować, lubić, potrzebować, słyszeć, widzieć and woleć
    the two plural forms are created as in the conjugation group 1
The 3rd person singular and plural forms (including polite addresses) use the word niech before the verb. Alternatively you can use proszę for that too.
 

Passive voice:
The passive voice is used to express actions done to a subject (as in English).
Formation:
Perfective verbs:
    Past: został/a/o (singular), zostali/zostały (plural)
    Future: zostanie (singular), zostaną (plural)
    Conditional: został/a/o + by (singular), zostali/zostały + by (plural)
Imperfective verbs:
    Present: jest (singular), są (plural)
    Past: był/a/o (singular), byli/były (plural)
    Future: będzie (singular), będą (plural)
    Conditional: był/a/o + by (singular), byli/były + by (plural)
+ adjectival participle passive

Negation:
The particle nie belongs before the verb.

Present tense:
This tense is only available for imperfective verbs. It expresses action in progress, repeated and habitual actions.
Perfective verbs conjugated this way express the simple future.

być:

ja	jestem
ty	jesteś
on/ona/one	jest
my	jesteśmy
wy	jesteście
oni/one	są

Conjugation 1:

ja	-am
ty	-asz
on/ona/one	-a
my	-amy
wy	-acie
oni/one	-ają

Conjugation 2:

ja	-em
ty	-esz
on/ona/one	-e
my	-emy
wy	-ecie
oni/one	-eją / -edzą

Conjugation 3a:

	ować, ywać, iwać	awać
ja	-uję	-aję
ty	-ujesz	-ajesz
on/ona/ono	-uje	-aje
my	-ujemy	-ajemy
wy	-ujecie	-ajecie
oni/one	-ują	-ają

Conjugation 3b:
Here some just the ć is replaced.

ja	-ję
ty	-jesz
on/ona/ono	-je
my	-jemy
wy	-jecie
oni/one	-ją

Conjugation 3c:

ja	-ę
ty	-esz
on/ona/ono	-e
my	-emy
wy	-ecie
oni/one	-ą

Some consonant changing at the stem end do occur here:
verbs in ać: r -> rz; s ->sz; k->cz; z->ż; m->mi; p->pi; t->cz; w- >wi
all other: g-> ż; r->rz; k->cz

Conjugation 3d:

ja	-ę
ty	-esz
on/ona/ono	-e
my	-emy
wy	-ecie
oni/one	-ą

Verbs in ąć add a "n" or "m" before the ending. Sometimes consonants change then too.

Conjugation 3e:

ja	-ę
ty	-esz
on/ona/ono	-e
my	-emy
wy	-ecie
oni/one	-ą

Here the following changes occur: s->si; n-> ni; z->zi; t->ci; d->dzi

Conjugation 4a:

ja	-ię
ty	-isz
on/ona/ono	-i
my	-imy
wy	-icie
oni/one	-ią

Conjugation 4b:

ja	-ę
ty	-isz
on/ona/ono	-i
my	-imy
wy	-icie
oni/one	-ą

Here these consonant changing occur at the stem end: si-> sz; zi -> ż; ści -> szcz; ździ -> żdż
Verbs in ioć, eić and ać add a "j" before the ę and the ą in the endings.

Conjugation 4c:

ja	-ę
ty	-ysz
on/ona/ono	-y
my	-ymy
wy	-ycie
oni/one	-ą

Past tense:
Unlike as in the present tense, there are different forms for males, females and neuters in singular. And male and non-male in plural.
To form this tense, you cut off the ending ć from the verb and add one of these endings:

	masculine singular	feminine singular	neuter singular	men plural	non-men plural
1st	-łem	-łam		-liśmy	-łyśmy
2nd	-łeś	-łaś		-liście	-łyście
3rd	-ł	-ła	-ło	-li	-ły

But there are some exceptions:
1) verbs in eć change the e to an "a" before ł.
2) verbs in ąć and nąć change the ą to ę except in the masculine singular form.
3) verbs in c, ść and żś:
        imperfective: insert the same consonant as in their present tense before the l or ł
        perfective: insert the same consonant as in the present tense of their imperfective counterpart

Future tense:
There are two ways for formation for imperfect verbs.
1) The future form of być + infinitive of the verb
2) The future form of być + past tense of the verb

	singular	plural
1st	będę	będziemy
2nd	będziesz	będiecie
3rd	będzie	będą

For perfective verbs, the future forms are conjugated as they would in present tense.

Irregular forms:
dać : dam, dadz, da, damy, dacie, dadzą
pomóc : pomogę, pomożesz, pomoże, pomożemy, pomożecie, pomogą
pójść : pójdę, pójdziesz, pójdzie, pójdziemy, pójdziecie, pójdą
wejść : wejdę, wejdziesz, wejdzie, wejdziemy, wejdziecie, wejdą
wyjść : wyjdę, wyjdziesz, wyjdzie, wyjdziemy, wyjdziecie, wyjdą
dojść : dojdę, dojdziesz, dojdzie, dojdziemy, dojdziecie, dojdą
przyjść: przyjdę, przyjdziesz, przyjdzie, przyjdziemy, przyjdziecie, przyjdą

Conditional tense:
Function:
    wishes and polite requests
    polite but somewhat aggressive commands
    commands, fears, advice, doubts or wishes in sub-clauses (after żeby)
    hypothetical conditions in present, past or future (possible + impossible)

Formation:
    take the 3rd person singular or plural of the past tense plus these endings:

	singular	plural
1st	-bym	-byśmy
2nd	-byś	-byście
3rd	-by	-by

usually one uses perfective verbs, but for regular desired (etc.) actions you have to use imperfect verbs.

Modal auxiliary verbs:
There are 6 modal auxiliary verbs in the Polish language: chcieć, mieć, móc, musieć, potrafić and powinienem. These are followed by an infinitive verb although chcieć and mieć can be used as normal verbs as well, then they are not followed by an other verb.
chcieć = to want
musieć = to have to, must (negative is "do not have to"!)
móc = to be able/allowed
mieć = to be supposed
potrafić = to know
powinienem = should