The usage of the primary prepositions do+genitive (G) and na+accusative (A) in speech is rather difficult for people speaking foreign language. In case of a range of mountains the preposition do+G is usually connected with the plural (do Krkonoš), while the preposition na+A with the singular (na Šumavu).
Nevertheless, in practical speech we can meet with exceptions. In this study the occurence of prepositions for les - forest (do českého lesa), pohoří - range of mountains (do pohoří Rila), vrch - hill (na Žď árské vrchy) and výšina - height (na Golanské výšiny) is analysed.
The distribution of the above prepositions is commented briefly from linguo-didactic point of view.