Modale Passiversatzformen (sein + zu + Infinitiv)
Grammar Rule in 30 Seconds
Use 'sein + zu + Infinitiv' to express necessity or possibility, functioning like a passive construction with 'müssen' or 'können'.
- Expresses necessity: 'Die Aufgabe ist zu erledigen' (The task must be done).
- Expresses possibility: 'Das ist kaum zu glauben' (That is hardly to be believed).
- The construction is always passive in meaning, even if the verb is active.
Overview
müssen, können, and werden all in one breath. It sounds like a wordy textbook from 1950. There is a sleeker way to speak. Meet the sein + zu + Infinitiv structure. This is the hidden passive of the German language. It is elegant. It is professional. It makes you sound like a C2 native expert. Think of it as the tuxedo of German grammar. You might not wear it to buy a kebab. However, you definitely want it for your next board meeting. This structure replaces passive modal verbs. It tells us what must be done or what can be done. It is concise and powerful. Let’s dive into how you can master it.How This Grammar Works
Das Problem muss gelöst werden. That is four words just for the verb part! With our new trick, you say: Das Problem ist zu lösen. It means exactly the same thing. The verb sein acts as the engine. The zu and the Infinitive act as the cargo. It carries the meaning of either necessity or possibility. How do you know which one it is? Context is your best friend here. Usually, in a positive sentence, it means "must." In a negative sentence, it often means "cannot." It is like a grammar chameleon. It changes its vibe based on the words around it.
Formation Pattern
sein. Match it to your subject.
zu right before the end.
Die Dokumente (Subject) + sind (sein) + zu (zu) + unterschreiben (Infinitive).
Die Dokumente sind zu unterschreiben. (The documents must be signed).
zu crawls inside. Example: vorbereiten becomes vorzubereiten. It is like a little grammar sandwich.
When To Use It
Das ist nicht zu fassen? That is this exact rule! They are saying "That is not to be grasped" (It is unbelievable). It adds a layer of sophistication to your speech that basic modals just cannot reach.
When Not To Use It
Das Bier ist zu trinken. Your friends will think you have turned into a robot. It is too stiff for casual hangouts. Also, avoid it if the "doer" of the action is the most important part. This structure focuses entirely on the object. If you want to say "I must do this," stick to Ich muss das tun. Das ist zu tun removes you from the sentence entirely. Use it only with transitive verbs. These are verbs that take a direct object. You cannot really use it with verbs like schlafen or gehen. Es ist zu gehen sounds more like a philosophical riddle than a normal sentence.
Common Mistakes
haben + zu. They look similar but are opposites. Sein + zu is passive. Haben + zu is active. If you say Der Chef ist zu sprechen, it means the boss is available to be spoken to. If you say Der Chef hat zu sprechen, it means the boss has to give a speech. Don't mix them up unless you want a very confused boss! Another mistake is forgetting the zu. Without it, the sentence just falls apart. Also, keep an eye on your endings. Since sein is the main verb, it must agree with the subject. If the subject is plural, use sind. If it is singular, use ist. Simple, right? Think of it like a grammar traffic light; green means go, but red (a missing zu) means a total crash.Contrast With Similar Patterns
Das kann gemacht werden. This is safe but wordy. Then you have the sich lassen + Infinitive: Das lässt sich machen. This also means "That can be done." It feels a bit more modern and flexible. Our sein + zu pattern is the most formal of the three. It carries more "weight." While sich lassen usually implies possibility, sein + zu often implies a strong obligation. If a sign says Rauchen ist zu unterlassen, it is not a suggestion. It is a command. It is much stronger than Hier darf nicht geraucht werden. Use sein + zu when the rule is non-negotiable.Quick FAQ
Does it always mean "must"?
Not always. In negative sentences, it often means "cannot." Das ist nicht zu ändern means "That cannot be changed."
Can I use it in the past tense?
Yes! Just change sein to war. Die Aufgabe war zu lösen (The task had to be solved).
Is this common in spoken German?
Only in specific set phrases or very formal contexts. In a casual chat, it is quite rare.
Can I use it with reflexive verbs?
Generally, no. It works best with simple transitive verbs like lesen, schreiben, or tun.
Formation with 'sein'
| Subject | sein | zu | Infinitive | |
|---|---|---|---|---|
|
Das
|
ist
|
zu
|
erledigen
|
|
|
Die {die|f} Aufgaben
|
sind
|
zu
|
erledigen
|
|
|
Es
|
war
|
zu
|
erledigen
|
|
|
Das
|
ist
|
nicht
|
zu
|
erledigen
|
Meanings
This construction acts as a modal passive, replacing 'müssen' (necessity) or 'können' (possibility) in passive sentences.
Necessity
Something must be done (equivalent to 'müssen' + passive).
“Das ist heute noch zu erledigen.”
“Die {die|f} Rechnung ist bis morgen zu bezahlen.”
Possibility
Something can be done (equivalent to 'können' + passive).
“Das ist kaum zu fassen.”
“Die {die|f} Lösung ist leicht zu finden.”
Reference Table
| Form | Structure | Example |
|---|---|---|
|
Affirmative
|
sein + zu + Inf
|
Das ist zu tun.
|
|
Negative
|
sein + nicht + zu + Inf
|
Das ist nicht zu tun.
|
|
Question
|
sein + Subj + zu + Inf
|
Ist das zu tun?
|
|
Past
|
war + zu + Inf
|
Das war zu tun.
|
|
Possibility
|
sein + zu + Inf
|
Das ist zu schaffen.
|
|
Necessity
|
sein + zu + Inf
|
Das ist zu bezahlen.
|
Formality Spectrum
Die {die|f} Aufgabe ist zu erledigen. (Workplace)
Die {die|f} Aufgabe muss erledigt werden. (Workplace)
Man muss die Aufgabe machen. (Workplace)
Mach das mal. (Workplace)
Modal Passive Logic
Meaning
- Müssen Must
- Können Can
Examples by Level
Das ist zu machen.
This must be done.
Das ist nicht zu sehen.
That cannot be seen.
Die {die|f} Arbeit ist heute zu beenden.
The work must be finished today.
Das ist leicht zu verstehen.
That is easy to understand.
Die {die|f} Regeln sind genau zu befolgen.
The rules must be followed exactly.
Das ist kaum zu glauben.
That is hard to believe.
Der {der|m} Antrag ist bis Freitag einzureichen.
The application must be submitted by Friday.
Das Problem ist nicht zu lösen.
The problem cannot be solved.
Die {die|f} Konsequenzen sind sorgfältig zu prüfen.
The consequences must be carefully examined.
Das ist unter keinen Umständen zu tolerieren.
That is not to be tolerated under any circumstances.
Die {die|f} vorliegenden Daten sind kritisch zu hinterfragen.
The available data must be critically questioned.
Das ist als Erfolg zu werten.
That is to be considered a success.
Easily Confused
Learners often use standard passive when this is more elegant.
Common Mistakes
Das ist machen.
Das ist zu machen.
Das ist zu gemacht.
Das ist zu machen.
Das sein zu machen.
Das ist zu machen.
Ich bin zu gehen.
Das ist zu gehen.
Das ist zu tun gewesen.
Das war zu tun.
Das ist zu nicht tun.
Das ist nicht zu tun.
Das muss zu tun sein.
Das ist zu tun.
Das ist zu erledigt.
Das ist zu erledigen.
Das ist zu haben gemacht.
Das war zu machen.
Die {die|f} Aufgabe ist zu sein erledigt.
Die {die|f} Aufgabe ist zu erledigen.
Das ist zu werden gemacht.
Das ist zu machen.
Es ist zu tun gewesen sein.
Es war zu tun.
Sentence Patterns
Die {die|f} ___ ist zu ___.
Real World Usage
Die {die|f} Frist ist zu beachten.
Focus on Necessity
Smart Tips
Replace 'muss gemacht werden' with 'ist zu machen'.
Pronunciation
Stress
Stress the infinitive verb.
Statement
Das ist zu TU-en.
Neutral declaration
Memorize It
Mnemonic
Think of 'sein + zu' as a 'Must-Do' or 'Can-Do' sticker on a task.
Visual Association
Imagine a red stamp on a document that says 'TO BE DONE'.
Rhyme
Sein plus zu, macht den Satz im Nu, passiv und fein, so muss es sein!
Story
The boss hands me a file. He says, 'Das ist zu lesen.' I read it. Then he says, 'Das ist zu unterschreiben.' I sign it. It is all about what must be done.
Word Web
Challenge
Write 5 sentences about your daily chores using this structure.
Cultural Notes
This structure is beloved in German officialdom for its brevity and objective tone.
Derived from Middle High German, where 'zu' + infinitive indicated purpose or necessity.
Conversation Starters
Was ist heute noch zu erledigen?
Journal Prompts
Common Mistakes
Test Yourself
Die {die|f} Arbeit ist ___ (erledigen).
Score: /1
Practice Exercises
1 exercisesDie {die|f} Arbeit ist ___ (erledigen).
Score: /1
FAQ (1)
Yes, but it sounds very formal.
Scaffolded Practice
1
2
3
4
Mastery Progress
Needs Practice
Improving
Strong
Mastered
In Other Languages
être + à + infinitif
German is more strictly used for modal passive.
ser + de + infinitivo
Spanish usage is less common than German.
〜べきである
Japanese is a suffix, not a separate verb construction.
يجب أن
Arabic does not use an infinitive structure like German.
Learning Path
Prerequisites
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