As with some other words, like _pravi_, _provi_, _provi_, the case of _verko_ and _vorko_ make morphologically apparent a semantic link with a vowel change, as it often occurs in Semitics languages. So, I would translate *verko* with *work*. That's probably the closest single word counterpart, although the semantic fields of each term greatly differ. Now, I recently discovered *vorko*, that PIV define as *Grava konstruaĵo (aŭtovojo, ponto, tunelo ks)*. Is their a better suited translation than *work* for *vorko*, so one might translate a discourse containing both *verko* and *vorko* in English?