Perfects

English:

Any verb in the perfect tense will be using the helping verbs "has", "have", or "had" and will have perfective aspect.

I have run.

She had finished the test last Thursday.

Greek:

Verbs in the perfect tense reduplicate, as here:

πεπιστευκα – I have believed

See BBG chapter 25 or this video. Perfects often have κα as their tense formative:

λελυκα– I have loosed

Hebrew:

QTL forms are sometimes called "perfects."