I. Theory
Modal verbs are often used in conjunction with other infinitives to convey ability, volition, or necessity. Examples in English include: can, want, and must. Although these verbs have both Perfekt (haben gekonnt) and Präteritum (konnten) forms, each is found in specific contexts.II. Modal Verbs in Perfekt (present perfect)
German modal verbs are found in the present perfect only when they do not accompany an infinitive. This is rare as most of the time, an infinitive is necessary. However, infinitives are sometimes inferred by context. The modal past participles are: gedurft, gekonnt, gemocht, gemusst, gesollt, and gewollt.| Sie hat kein Deutsch gekonnt. She couldn’t (speak) German. Gestern habe ich in die Stadt gemusst. Yesterday, I had (to go) into the city. Das habe ich nicht gewollt. I didn’t want that. |
III. Modal Verbs in Präteritum
German modal verbs are very often found in the imperfect when in the past. In this form, they are able to used in conjunction with the infinitive just like in the present tense.|
Wir konnten den Reiseführer nicht verstehen, da er nur Chinesisch sprach. We couldn’t understand the travel guide since he only spoke Chinese. Während des Krieges mussten sie aus ihrem Land fliehen. During the war they had to flee their country. Ich wollte den ganzen Abend mit ihm reden, aber er war zu beschäftigt. I wanted to talk to him all night but he was too busy. |
IV. Helper Verb with a Double Infinitive
An alternative to a modal verb in simple past + an infinitive is having both the verbs as infinitives with haben as a helper verb. This construction conveys the same meaning as the simple past modal + infinitive, though the double infinitive isn’t seen as often.| Ich musste ein Geschenk für meine Mutter kaufen. I had to buy a gift for my mother. Or Ich habe ein Geschenk für meine Mutter kaufen müssen. I had to buy a gift for my mother. Vor dem Regen wollten die Kinder im Garten spielen. Before the rain, the children wanted to play in the yard. Or Vor dem Regen haben die Kinder im Garten spielen wollen. Before the rain, the children wanted to play in the yard. Früher durfte man im Restaurant rauchen. Earlier one was allowed to smoke at restaurants. Or Früher hat man im Restaurant rauchen dürfen. Earlier one was allowed to smoke at restaurants. |
Note: If the double infinitive is part of a subordinating clause, the helper verb goes into the second to last position.
| Er hat ins Krankenhaus gehen müssen. He had to go to the hospital. But Ich glaube, dass er ins Krankenhaus hat gehen müssen. I don’t think you should have said that. Sie hat nicht auf die Reise gehen können. She couldn’t go on the trip. But Ich weiß nicht, ob sie auf die Reise hat gehen können. I don’t know, whether she was able to go on the trip. |