Infinitive clauses with and without "zu" (um zu = "in order to", ohne zu = "without (doing)", anstatt zu = "instead of (doing)", lassen + Infinitiv = "let/allow/have + infinitive")

Infinitive clauses with and without "zu" (um zu, ohne zu, anstatt zu, lassen + Infinitiv)

This article explains how German forms infinitive clauses with and without the particle zu. You will learn what these clauses mean, when to use zu (or not), how to form them (including separable verbs), and which common mistakes to avoid. Many clear German examples are given, each with an English translation.

1. What is an infinitive clause?

An infinitive clause (Infinitivgruppe) is a phrase built around an infinitive verb (the base verb form), sometimes introduced by the particle zu. In English you often translate these with "to + verb" (to go, to do) or with -ing forms (doing) depending on the context.

Examples:
- Ich hoffe, dich bald zu sehen. — I hope to see you soon.
- Er hat beschlossen, nach Berlin zu ziehen. — He decided to move to Berlin.

Infinitive clauses can act as complements to verbs, adjectives, or nouns, or can express purpose, manner, or contrast.

2. When do I use "zu" and when not? (Overview)

Use zu:
- After many verbs that take an infinitive clause: versuchen, hoffen, planen, beschließen, versprechen, etc.
- After nouns and adjectives that are followed by an infinitive: die Möglichkeit, die Absicht, wichtig, leicht, schwer, bereit, etc.
- In purpose expressions with um ... zu (in order to).
- In constructions with ohne ... zu and anstatt (statt) ... zu.
- With most verbs where the infinitive clause is subordinate and the subject is the same.

Do NOT use zu (use the bare infinitive):
- After modal verbs: können, müssen, dürfen, sollen, wollen, mögen. (Ich kann schwimmen.)
- After lassen (in the sense of "let/leave/have someone do something"). (Ich lasse ihn gehen.)
- After verbs of perception: sehen, hören, fühlen, beobachten (with an object + bare infinitive). (Ich sah das Kind fallen.)
- In many fixed expressions and verbs of motion + activity: gehen, kommen (Ich gehe schwimmen.)

3. How is "zu" formed and where does it go?

- Basic placement: zu is placed directly before the infinitive stem: „zu + Infinitiv". Example: lernen + zu lesen -> zu lesen.
- Ich lerne, Deutsch zu sprechen. — I am learning to speak German.

- With separable-prefix verbs, zu goes between the prefix and the verb stem:
- aufstehen -> aufzustehen.
- Ich versuche, früh aufzustehen. — I try to get up early.
- mitkommen -> mitzukommen.
- Wir hoffen, dass du mitkommst -> Wir hoffen, mitzukommen (used as infinitive phrase: Es ist unser Plan, zusammen mitzukommen).

- With inseparable prefixes (be-, ver-, er-, ent-, emp-), zu is placed before the whole verb: verstehen -> zu verstehen.
- Das ist schwer zu verstehen. — That is hard to understand.

- Negative: put nicht before zu or inside the construction where appropriate. With um ... zu negative purpose use "um ... nicht zu":
- Ich arbeite leise, um die anderen nicht zu stören. — I work quietly so as not to disturb the others.

4. "um ... zu" — purpose (in order to)

Meaning: "um ... zu" expresses purpose and often translates as "in order to".

Important rule: The subject of the main clause and the infinitive clause with "um zu" must be the same. If the subjects are different, use a finite clause with "damit".

Examples:
- Ich lerne Deutsch, um in Deutschland zu studieren. — I study German in order to study in Germany. (same subject: ich)
- Er spart Geld, um ein Auto zu kaufen. — He saves money to buy a car. (same subject)

Incorrect (subjects different):
- *Ich rufe an, um du zu fragen. — Wrong. (Subjects differ: I vs you.)
- Correct: Ich rufe an, damit du fragen kannst. — I call so that you can ask.

Use the negative form when the purpose is to avoid something:
- Sie ging leise, um die Kinder nicht zu wecken. — She walked quietly so as not to wake the children.

5. "ohne ... zu" — without doing something

Meaning: "ohne ... zu" = without doing X (the -ing form in English).

Subject rule: Like "um zu", the subject of the main clause and the infinitive clause introduced by "ohne zu" must normally be the same. If they differ, use "ohne dass" + finite clause.

Examples:
- Er ging weg, ohne sich zu verabschieden. — He left without saying goodbye.
- Sie verließ das Haus, ohne das Licht auszuschalten. — She left the house without turning off the light.

Different subject (use ohne dass):
- Er verließ das Zimmer, ohne dass ich es bemerkt hätte. — He left the room without my noticing it.

6. "anstatt (statt) ... zu" — instead of

Meaning: "anstatt zu" or "statt zu" expresses that one action happens in place of another: "instead of ... -ing".

Examples:
- Statt zu arbeiten, ging er spazieren. — Instead of working, he went for a walk.
- Anstatt zu fragen, nahm sie das Buch. — Instead of asking, she took the book.

If the subjects differ or you prefer a full clause, you can use "anstatt dass" or restructure the sentence with a finite clause.

7. "lassen" + Infinitiv (no "zu") — let / have / cause

Basic uses (no "zu"):
- Allowing/letting: Ich lasse dich gehen. — I let you go.
- Having something done (causative): Ich lasse mein Auto reparieren. — I have my car repaired.
- Leaving something in a state: Ich lasse das Fenster offen. — I leave the window open.

Structure notes:
- LASSEN + object + bare infinitive: Ich lasse + ihn + gehen.
- When used in passive-like or idiomatic forms, you may see "sich lassen" or "Das lässt sich machen." — That can be done.

Examples:
- Er lässt seine Kinder draußen spielen. — He lets his children play outside.
- Ich lasse mein Fahrrad reparieren. — I have my bicycle repaired.
- Das lässt sich nicht ändern. — That cannot be changed.

8. Verbs that normally take the bare infinitive (no "zu")

- Modal verbs: können, müssen, dürfen, sollen, wollen, mögen.
- Ich kann schwimmen. — I can swim.
- Verbs of perception with an object: sehen, hören, fühlen, beobachten.
- Ich sah ihn den Ball fangen. — I saw him catch the ball.
- Causative/letting verbs: lassen.
- Sie ließ die Tür offen. — She left the door open.
- Some motion verbs in certain uses: gehen (Ich gehe schwimmen.)

Note: Some verbs allow both forms in different meanings (e.g., lernen: Ich lerne schwimmen. / Ich lerne, Deutsch zu sprechen.). Context matters.

9. Adjectives and nouns followed by "zu" + infinitive

Many adjectives and nouns are followed by a zu-infinitive to express possibility, necessity, willingness, or purpose.

Examples:
- Das Buch ist leicht zu lesen. — The book is easy to read.
- Es ist wichtig, pünktlich zu sein. — It is important to be on time.
- Die Möglichkeit, ihn zu treffen, war groß. — The possibility of meeting him was big.

Special construction: "sein zu + Infinitiv" often expresses that something has to be done (formal/impersonal obligation):
- Die Aufgabe ist bis morgen zu erledigen. — The task must be completed by tomorrow.
- Das Haus ist zu verkaufen. — The house is for sale / the house needs to be sold.

10. More formation tips: commas, placement, and small tricks

- Commas: It is common (and often clearer) to separate the main clause and the infinitive clause with a comma, especially for longer clauses or with um/ohne/anstatt.
- Ich habe beschlossen, morgen anzufangen. — I decided to start tomorrow.

- "Für + noun + zu + Infinitiv": When the subject of the infinitive clause is not the same as the main clause, you can sometimes mark the different subject with "für":
- Es ist wichtig für mich, ihn zu verstehen. — It is important for me to understand him. (Here the subject of the infinitive is still logical: "I".)

- If subjects differ in purpose/contrast contexts, prefer finite subordinate clauses with "damit", "ohne dass", or "anstatt dass".

11. Common mistakes and how to avoid them

- Mistake: Using "um zu" when the subjects differ.
- Wrong: *Ich rufe an, um du zu fragen.
- Correct: Ich rufe an, damit du fragen kannst.

- Mistake: Adding "zu" after modal verbs.
- Wrong: *Ich kann zu schwimmen.
- Correct: Ich kann schwimmen.

- Mistake: Forgetting to insert zu correctly with separable verbs.
- Wrong: *Ich versuche, früh aufzustehen -> (if written as "Ich versuche, aufzustehen früh" would be wrong). Keep the correct form: Ich versuche, früh aufzustehen.

- Mistake: Using "ohne zu" when subjects differ.
- Wrong: *Er ging weg, ohne ich zu wissen.
- Correct: Er ging weg, ohne dass ich es wusste.

- Mistake: Using zu with "lassen" in causative/letting meaning.
- Wrong: *Ich lasse zu gehen.
- Correct: Ich lasse ihn gehen. / Ich lasse mein Auto reparieren.

12. Quick reference: common patterns with examples

- Verb + zu + Infinitive (same subject):
- Ich hoffe, dich bald zu sehen. — I hope to see you soon.
- um ... zu (purpose, same subject):
- Ich lerne viel, um die Prüfung zu bestehen. — I study a lot in order to pass the exam.
- ohne ... zu (without doing):
- Sie verließ das Haus, ohne sich anzumelden. — She left without signing in.
- statt/anstatt ... zu (instead of doing):
- Statt zu schlafen, arbeitete er die ganze Nacht. — Instead of sleeping, he worked all night.
- modal verbs (no zu):
- Du musst gehen. — You must go.
- perception verbs (no zu) with object + bare infinitive:
- Ich hörte ihn singen. — I heard him sing.
- lassen + object + bare infinitive:
- Ich lasse mein Fahrrad reparieren. — I have my bike repaired.
- adjective/noun + zu + Infinitive:
- Es ist schwierig, ihn zu verstehen. — It is difficult to understand him.

13. Glossary (short)

- Infinitive: the base form of a verb (gehen, sehen).
- Infinitive clause (Infinitivgruppe): a phrase built around an infinitive, sometimes introduced by zu.
- Separable-prefix verb: a verb with a prefix that separates in main clauses (aufstehen -> ich stehe auf).
- Modal verb: verbs like können/müssen/wollen that take a bare infinitive.
- Causative/letting: using "lassen" to let or have someone do something.
- Purpose clause: a clause expressing why something is done (use um ... zu or damit).

14. Final tips

- Ask yourself: Are the subjects the same? If yes, "um zu"/"ohne zu"/"statt zu" often work. If not, use "damit"/"ohne dass"/"anstatt dass" or restructure.
- Memorize the verbs that take the bare infinitive (modal verbs, perception verbs, lassen).
- Practice the placement of "zu" with separable prefixes: aufzustehen, mitzukommen, auszuschalten.
- When in doubt, use a comma before long infinitive phrases and check whether the subject fits.

If you want, I can now give a compact list of verbs that typically take "zu" and a separate list that take the bare infinitive (modal verbs, perception verbs, lassen), or provide more examples for any of the specific patterns above.