"I will eat the sandwich."
Translation:Εγώ θα τρώω το σάντουιτς.
So, does Greek have essentially a complete set of perfective and imperfective paired verbs, like Slavic languages?
I too have been given to understand that there is some terminological distinction between perfect and perfective, though I have no idea why a future perfect, for instance, would not be perfective. In any case, all of my linguistic terminology is both dimly understood and decades out of date.
Greek verbs usually have two stems: present and aorist. The present stem is used mostly for the present indicative, present subjunctive (used e.g. in imperfective future), and imperfect; the aorist stem mostly in the aorist indicative (with a generally past meaning) and aorist subjunctive (used e.g. in perfective future).
They don't form perfective by adding a prefix, and so you can't have one imperfective verb corresponding to several perfective ones as in Slavic.
Nearly all verbs have both stems, but some only have one, meaning that they can only be used in one aspect -- for example, είμαι only has a present stem and so doesn't form perfective aspect. (Sometimes υπήρξα from υπάρχω is used as a quasi-aorist of είμαι.) Another example is ξέρω which has ήξερα but no other stem.
Often, those will be state verbs where single-event doesn't make much sense: you don't "be" or "know" just once, you usually do it over a period of time, even if in English we don't say "I am knowing that fact".
So they don't feel like paired verbs to me, just like two stems of one and the same verb.
Yes, "to eat" has the stems τρω(γ)- and φα(γ)-; it's one of the more irregular ones.
I think that those stems used to be separate verbs as well (τρώγω "chew" and εσθίω, φαγ- "eat"), a bit like how the nearly-obsolate "wend" supplied the past participle "went" for the English verb "to go".
Similarly with (ε)ιδ-, the aorist stem that is now paired with βλεπ- but which used to be paired, I think, with οράω.
In most cases, though, the relationship is a bit more obvious even where the stems differ a bit from each other.
I remember once, when I was at the beginning of learning Greek, seeing the verb έπεσε and struggling to find the dictionary form of that verb; I knew enough to know that the έ was likely a temporal augment and not part of the stem and that -σ- was probably the sign of the aorist and similarly not part of the stem, but I guessed the verb might be πέζω... turned out it's πέφτω, and the whole -φτ- got swallowed by the -σ-.