Present tense of separable verbs
The infinitive of a verb (the form you find in the dictionary) is made up of a stem and the ending –en (-n).
In the present tense, this ending is replaced by different endings depending on person and number. However, there are a number of irregular verbs that have different forms.
Separable verbs consist of two parts.
In main clauses in the present tense, the first part of a separable verb is separated from the (conjugated) stem verb and stands at the end of the sentence or clause.
aufstehen: Ich stehe um 7 Uhr auf.
anrufen: Er ruft seine Mutter an.
einladen: Wir laden unsere Freunde ein.
zumachen: Sie macht das Fenster zu.