Participles

Participles are used for forming the past tense, conditionals and the passive voice.
They also express gender which must correspond with the gender of the subject.

Past participle
The past participle is used for forming the past tense and the conditionals.
The subject is also the executor of the action.

Form:
Infinitive (minus ending -t) + suffix (l - li, la - ly, lo - la)

suffixes for singular - plural
Masculine: l - li
Feminine: la - ly
Neuter: lo - la

být - to be
on byl - oni byli (he was - they were)
ona byla - ony byly (she was - they were)
ono bylo - ona byla (it was - they were)

dělat - to do
on dělal - oni dělali (he did - they did)
ona dělala - ony dělaly (she did - they did)
ono dělalo - ona dělala (it did - they did)

sedět - to sit
on seděl - oni seděli (he sat - they sat)
ona seděla - ony seděly (she sat - they sat)
ono sedělo - ona seděla (it sat - they sat)

Passive participle
The passive participle is used for forming the passive voice.
The subject is not the actor of the action, it is only affected by the action, he suffers the action.
There are two types of endings:

Form:
Infinitive (minus ending -t) + suffix (t - ti, ta - ty, to - ta or ni, na - ny, no - na)

1. type suffixes:
(for singular - plural)
Masculine: t - ti
Feminine: ta - ty
Neuter: to - ta

2. type suffixes:
(for singular - plural)
Masculine: n - ni
Feminine: na - ny
Neuter: no - na

The passive voice can be expressed in two ways:
a) to be + passive participle

dělat - to do
on byl dělán - oni byli děláni (he was being done, they were being done)
ona byla dělána - ony byly dělány (she was being done, they were being done)
ono bylo děláno - ona byla dělána(it was being done, they were being done)

psát - to write
on byl napsán - oni byli napsáni (he was written, they were written)
ona byla napsána - ony byly napsány (she was written, they were written)
ono bylo napsáno - ona byla napsána (it was written, they were written)

nabít - to charge
on byl nabit - oni byli nabiti (he was charged, they were charged)
ona byla nabita - ony byly nabity (she was charged, they were charged)
ono bylo nabito - ona byla nabita (it was charged, they were charged)

b) 3rd. person + past participle + se
napsat - to write
napsalo se - napsala se (it was written, they were written)

vyrobit - to make
vyrobilo se - vyrobila se (it was made, they were made)