Separable Prefixes in German

Many common verbs in German belong to a category called separable-prefix verbs or inseparable-prefix verbs. In general, they are conjugated just like all other German verbs, but you need to know what happens to the prefix when you use these verbs.

Separable prefixes, as the name implies, usually (but not always) separate from the basic verb stem. German separable-prefix verbs can be compared to English verbs like "call up," "clear out" or "fill in." While in English you can say either "Clear out your drawers" or "Clear your drawers out," in German the separable prefix is almost always at the end, as in the second English example.

A German example with anrufen: Heute ruft er seine Freundin an. = Today he's calling his girlfriend (up).

How Are Separable Prefixes Used?

Commonly used separable prefixes include ab-, an-, auf-, aus-, ein-, vor- and zusammen-. Many common verbs use separable prefixes: abdrehen (to turn/switch off), anerkennen (to recognize [officially]), aufleuchten (to light up), ausgehen (to go out), sich einarbeiten (to get used to the work), vorlesen (to read aloud), zusammenfassen (to summarize).

There are three situations in which the "separable" prefix doesn't separate:

(1) in the infinitive form (i.e., with modals and in the future tense),
(2) in dependent clauses, and (3) in the past participle (with ge-). 
An example of a dependent clause situation would be:

 "Ich weiß nicht, wann erankommt." (I don't know when he's arriving.) 

In spoken German, separable verb prefixes are stressed (betont): AN-kommen.

All of the separable-prefix verbs form the past participle with ge-, with the prefix located in front of and attached to the past participle. Examples: Sie hat gestern angerufen, She called/telephoned yesterday. Er war schon zurückgefahren, He had already gone back.

Here are some sample sentences in various tenses with the verb anfangen.

Sample Sentences with the separable-prefix verb anfangen, to begin, start
D E U T S C H	E N G L I S H
P r e s e n t   T e n s e
Wann fangen Sie an?	When do you begin?
Ich fange heute an.	I start today.
P r e s .   P e r f e c t   T e n s e
Wann haben sie angefangen?	When did they begin?
P a s t   P e r f e c t   T e n s e
Wann hatten Sie angefangen?	When had you begun?
P a s t   T e n s e
Wann fingen wir an?	When did we begin?
F u t u r e   T e n s e
Wir werden wieder anfangen.	We will begin again.
W i t h   M o d a l s
Können wir heute anfangen?	Can we begin today?

What Are Inseparable Prefixes?

Inseparable prefixes include be-, emp-, ent-, er-, ver- and zer-. Many common German verbs use such prefixes: beantworten (to answer), empfinden (to sense, feel), entlaufen

(to get/run away), erröten (to blush), verdrängen (to oust, replace), zerstreuen (to disperse, scatter). The inseparable verb prefixes remain attached to the stem verb in all situations: "Ich versprechenichts." - "Ich kann nichts versprechen." In spoken German, inseparable verb prefixes are unstressed (unbetont). Their past participles do not use ge- ("Ich habe nichts versprochen.").