Abstract
The paper describes the results of an investigation carried out as part of systematic teaching of morphology at the beginning of tertiary students'course of the Czech language. The investigation focuses on the students'use of grammatical preconceptions in understanding the morphology of word formations.
The obtained results indicatte that the students often prefer (subconsciously) to classify adjectives derived from verbs as verbs, despite their formal characteristics, such as syntactic and other grammatical properties. As a result, de-verbal adjectives are wrongly categorized as verb.
The study suggests that monitoring the distribution of errors made by the students participating in the study may be revealing for understanding the underlying processes operating within the period of students' formation of grammatical preconceptions.