Just like in English, the German infinitive is the basic form of a verb (schlafen/to sleep). However, it is less frequently found than in English to be accompanied by the preposition zu/to. The following is an overview of specifics pertaining to the German infinitive.
THE ENDING OF GERMAN INFINITIVES
Most German infinitives end with -en (springen/to jump), but there are also some verbs that end in the infinitive with -ern, -eln, -n (wandern/to wander, hike, sammeln/to collect, sein/to be.)
TENSES AND MOODS
The German infinitive is used in the following tenses and moods: The future -> Er will morgen arbeiten. He wants to work tomorrow. Conjunctive II -> Mein Vater möchte gerne nach Köln reisen. In the passive -> Die Tür sollte verriegelt sein In the passive perfect -> Das Kind scheint zu spät angekommen zu sein. With modal verbs -> Der Junge soll die Banana essen, aber er will nicht.
INFINITIVES AS NOUNS
Infinitives can become nouns. No changes necessary. Only you must remember to precede the infinitive noun with the article das and to always capitalize it. -> das Liegen/the lying-down, das Essen– the food, das Fahren/the driving….
INFINITIVES AS SUBJECT
Some German infinitives can stand in as the subject of a sentence. Some of these are: anfangen, aufhören, beginnen, andenken, glauben, hoffen, meinen, vergessen, versuchen. For Example: Sie meint, sie hat immer recht -> Sie meint, immer recht zu haben – He thinks he is always right. Note: If you say – Sie meint, er hat immer recht – you can’t replace er with the infinitive, since the original subject of the sentence isn’t restated. Ich freue mich, dass ich ihn bald wiedersehe/I am happy that I will be able to see him again -> Ich freue mich ihn bald wiederzusehen/I’m happy to see him again.
CONJUGATED VERB + INFINITIVE
CONJUNCTION + INFINITIVE
NOUN + INFINITIVE