This paper will provide an account for the existence of pairs of deverbal nominals with
giving rise to event readings. We first study the argument structure of the bases and of the derived nominals, and establish the general tendencies. We further examine the Aktionsart of the nominalizations and of the verbal bases. We conclude that these levels of investigation are not sufficient to determine the proper contribution of the two nominalization patterns and further demonstrate that the relevant contribution they make is at the level of grammatical aspect. We therefore propose that
introduces the imperfective viewpoint, whereas
introduces the perfective viewpoint.