Although "gerunds" and "present participles" are morphologically identical, their grammatical functions differ substantially. Verbs additionally have an infinitive and two participles (present and past). There are also two participles (active and passive) and a verbal noun, but no infinitive. Causative verbs only require stem transformations for forming their perfect participles. The past participles of weak verbs decline as strong adjectives. Verbs have two infinitive forms&colon; bare, and bound; and two participles&colon; present, and past. There are no adjectives other than verbal nouns and participles. Verbs in forms using past participles also vary in voice and gender. This includes adjectives for materials, as well as the past participles of strong verbs. Pronouns, adjectives, participles, and some numerals also change their endings to show case and number. Sireniki Eskimo has several adverbial participles to express that. The form of these participles and verbal nouns is largely predictable. Ancient Greek makes frequent use of participles, which are verbal adjectives. Present participles, and a few nouns, ended in /nd/. Latin participles, like English participles, are formed from a verb.