Verb Conjugation used as a noun
Verb conjugation of regular I and regular II verbs, can be used as a noun when used by itself.
Desu can be used alongside adjectives in order to make the speech polite.
Doi-sensei no hanashi wa itsumo omoshiroi(desu).
Prof. Doi's talk is always interesting.
Kono shōhin wa mōke ga ōi (desu).
These goods bring in a large profit.