zum, zur, ins, beim, vom

German often joins a preposition and the article into one word. zu + dem becomes zum, zu + der becomes zur, in + das becomes ins, bei + dem becomes beim, and von + dem becomes vom. These short forms are normal in speech and in most writing. The full forms zu dem, in das and so on are possible, but they sound emphatic, so learners should use the short forms.

The article inside the short form still shows the case and the gender. zum, beim and vom contain dem, so they are masculine or neuter dative. zur contains der, so it is feminine dative. ins contains das, so it is neuter accusative, and it appears with movement towards a place. A common mistake is to keep the article: learners say zu dem Arzt or in das Kino where zum Arzt and ins Kino are the normal forms.