IB Diploma German B SL · Grammar backbone 5 of 10 — Modal verbs and infinitive constructions
IB German B Grammar
Modals and infinitives
The six modal verbs reshape a clause: they take the finite slot while the main verb drops to an infinitive at the end. This lesson also builds the zu-infinitive, the um…zu / ohne…zu / anstatt…zu constructions, and the tricky double infinitive.
modal (V2) … infinitive (end)Ich kann gut Deutsch sprechen.
Work through each screen and answer the questions — some ask you to spot the form, some to build it. Collect ⭐ and press Start.
This grammar backbone powers every IB German B theme: Identities, Experiences, Human ingenuity, Social organization and Sharing the planet — so you can build accurate texts across paper 1, paper 2 and the individual oral.
The six modals
Meaning and forms
Learn the six modals with their exact meanings. In the present they are irregular in the singular and take no -t in the er-form:
person
können (can)
müssen (must)
wollen (want)
ich
kann
muss
will
du
kannst
musst
willst
er/sie/es
kann
muss
will
wir/sie
können
müssen
wollen
False friend:will means "want", not "will"! The others: dürfen (may/allowed), sollen (should/supposed to), mögen / möchte (like / would like).
Quick check
Modal + infinitive
?Complete: Ich ___ gut Deutsch sprechen. ("I can speak German well.")
The pattern
Infinitive at the end
The modal is the finite verb, so it sits in position 2. The verb it governs becomes an infinitive and closes the bracket at the very end:
Wir müssen jetzt gehen.
Du darfst hier nicht rauchen.
Sie möchte einen Kaffee trinken.
Everything else — objects, adverbs, negation — sits between the modal and the final infinitive.
Type it
Your turn — the er-form
1Fill the modal: Er ___ heute arbeiten. ("He has to work today.") — from müssen, er-form.
Hint: modals take no -t in the er-form. ich and er share the same form here.
Sort it
Choose the correct form
Quick check
No -t in the er-form
?Complete: Er ___ jeden Tag Sport machen. ("He wants to do sport every day.") — from wollen.
zu + infinitive
When a verb needs zu
Many verbs and expressions govern a zu-infinitive (unlike modals, which take a bare infinitive): versuchen, hoffen, beginnen, vergessen, Lust haben, es ist wichtig…
Ich versuche, früh aufzustehen.
Es ist wichtig, viel zu üben.
Separable verbs: the zu slots inside the verb, between prefix and stem — aufstehen → aufzustehen, anrufen → anzurufen.
Quick check
zu with a separable verb
?Complete: Ich versuche, früh ___. ("I try to get up early.") — from aufstehen.
Type it
Your turn — zu-infinitive
2Fill the zu-infinitive: Ich habe keine Zeit, dich ___. ("I have no time to call you.") — from anrufen.
Hint: separable 'anrufen' → an-zu-rufen.
um … zu
Purpose, without and instead
Three infinitive constructions carry key meanings — all end in zu + infinitive:
um … zu — in order to: Ich lerne, um die Prüfung zu bestehen.
ohne … zu — without (doing): Er ging, ohne zu bezahlen.
(an)statt … zu — instead of (doing): Statt zu arbeiten, schlief er.
Same subject:um … zu works only when both clauses share a subject. If the subjects differ, use damit + a full clause instead.
Quick check
In order to
?Complete: Ich lerne viel, ___ die Prüfung zu bestehen. ("… in order to pass the exam.")
Game · Match
Match the modal to its meaning
Tap a modal on the left, then its English meaning.
MODAL
können
müssen
dürfen
sollen
wollen
mögen
MEANING
should / supposed to
can / be able to
to like
must / have to
to want to
may / be allowed to
Double infinitive
The perfect of a modal
When a modal governs another verb in the perfect, the modal itself appears as an infinitive, not a participle — giving a double infinitive, always with haben:
Ich habe gestern arbeiten müssen. — "I had to work." (not 'gemusst')
Er hat nicht kommen können. — "He couldn't come."
In a subordinate clause the auxiliary jumps in front of the double infinitive: …, weil ich habe arbeiten müssen.
Quick check
Perfect of a modal
?Complete: Ich habe gestern viel arbeiten ___. ("I had to work a lot yesterday.") — from müssen.
Type it
Your turn — infinitive at the end
3Fill the final infinitive: Wir müssen jetzt ___. ("We must go now.") — from gehen.
Hint: after a modal, the main verb stays an infinitive and closes the sentence.
Sort it
zu-infinitive, or bare infinitive?
Sort each word by what kind of infinitive follows it.
+ zu + Infinitiv
+ bare Infinitiv
Type it
Your turn — without doing
4Fill the connector: Er ging weg, ___ zu bezahlen. ("He left without paying.")
Hint: "without (doing)" = … zu + infinitive.
Type it
Your turn — a full sentence
5Translate "I want to learn German" into German (use wollen + lernen).
Hint: modal 'will' in second place, object 'Deutsch', infinitive 'lernen' at the end.
Recap
Your modal toolkit
Six modals: können, müssen, dürfen, sollen, wollen, mögen — irregular singular, no -t in er, and 'will' = wants.
Modal + infinitive: modal is V2, bare infinitive at the end.
zu-infinitive: after versuchen, hoffen, es ist wichtig… Separable verbs take zu inside (aufzustehen).
um/ohne/anstatt … zu; double infinitive in the perfect (haben … arbeiten müssen), with the auxiliary fronted in subordinate clauses.
Cluster 6 drills the case-governing power of prepositions — including the two-way Wechselpräpositionen. Press Finish.
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Next in the backbone: prepositions and cases, including the two-way prepositions.