Editing Infinitive (section)

===Ancient Greek===
{{Main|Infinitive (Ancient Greek)}}
In [[Ancient Greek]] the infinitive has four tenses (present, future, aorist, perfect) and three voices (active, middle, passive). Present and perfect have the same infinitive for both middle and passive, while future and aorist have separate middle and passive forms.

{| class="wikitable" style="text-align: center;"
! tense !! active !! middle !! passive
|-
! present
| {{lang|grc|παιδεύειν}}
| colspan="2" | {{lang|grc|παιδεύεσθαι}}
|-
! future
| {{lang|grc|παιδεύσειν}} || {{lang|grc|παιδεύσεσθαι}} || {{lang|grc|παιδευθήσεσθαι}}
|-
! aorist
| {{lang|grc|παιδεῦσαι}} || {{lang|grc|παιδεύσᾰσθαι}} || {{lang|grc|παιδευθῆναι}}
|-
! perfect
| {{lang|grc|πεπαιδευκέναι}}
| colspan="2" | {{lang|grc|πεπαιδεῦσθαι}}
|}

[[Thematic vowel|Thematic verbs]] form present active infinitives by adding to the stem the thematic vowel {{lang|grc|-ε-}} and the infinitive ending {{lang|grc|-εν}}, and contracts to {{lang|grc|-ειν}}, e.g., {{lang|grc|παιδεύ-ειν}}.  Athematic verbs, and perfect actives and aorist passives, add the suffix {{lang|grc|-ναι}} instead, e.g., {{lang|grc|διδό-ναι}}.  In the middle and passive, the present middle infinitive ending is {{lang|grc|-σθαι}}, e.g., {{lang|grc|δίδο-σθαι}} and most tenses of thematic verbs add an additional {{lang|grc|-ε-}} between the ending and the stem, e.g., {{lang|grc|παιδεύ-ε-σθαι}}.