The goal of the thesis is to contribute to the description of the category of aspect and to do so in an alternative way, i.e. without linking aspectual value of a sentence exclusively or directly to the morphological make-up of the verb. The starting point is the distinction between states and activities, i.e. between state and activity events. In the center of our attention are states, namely the way how states are expressed by perfective predicates. Two analyses of corpus data (SYN v7) were performed to pursue the issue. The first analysis focused on the occurrence of state and activity meanings of perfective forms of so-called capacitive verbs. It turns out that one of the decisive factors construing the aspectual meaning of a sentence is the category of tense. The other analysis focused on a collocation we have termed aspectual paradox. It combines durative adverbials (for instance stále) with perfective verbs in the framework of one construction. This analysis has demonstrated that another important factor involved in sentence aspectual construal is modality. Another outcome of this analysis is a classification of state meanings of the "durative adverbial + perfective" collocation. Eleven kinds of meanings were established: ability, possibility, existence, quality, quantity, etc. Verba...