sentences:  Infinitives are verbal nouns and, just like other nouns, are formed with suffixes.It is not clear whether any of the infinitive suffixes reconstructed from the daughter languages (', ', ", among others) was actually used to express an infinitive in PIE.Participles are verbal adjectives formed with the suffixes ' (active imperfective and aorist participle), ' (perfect participle) and ' or ' (mediopassive participle), among others.