The present article ties in with an earlier study by Chomsky (1970) on nominalizations in English, which was then refined primarily in the influential work of Jane Grimshaw (1990) and is dealt with in detail in Borer (2013) and in Kosta (2020). In contrast to the English gerundives, which do not lose verbal behavior due to the derivation in the syntax and maintain all grammatical categories and characteristics of verbs, which is why one can speak of a real conversion while preserving the verbal semantics, the situation is somewhat different in Czech. In the deverbal, deadjective and other derivations, the Czech apparently made the transition to the noun with its critical properties, which is shown by certain restrictions in the aspectuality marking of deverbal noun phrases on -ni-, -ti-, which, e.g., do not pass the progression durativity test (Vendler 1967). In passive constructions, as is well known, a valence point in the position of the external argument is reduced compared to the corresponding active sentences, while the external argument position in anti-causatives is also not available in the deep structure. In addition to the syntactic restrictions that are evident in nominalizations in the context of simple sentences of different sentence types (causative, anti-causative, passive) and demonstrate the nominal character of certain types of deverbal noun phrases in the first part of this article, the second part of the essay deals with more complex structures and extends its analytical and theoretical part to the phenomenon of nominalizing subordinate clauses. The aim of the central part of this contribution is therefore to test the nominal properties of embedded conjunctional sentences and of embedded headless relative sentences on the basis of empirical data and thus contribute to the knowledge of whether certain types of relative sentences can (or must) be nominalized.