“Das Problem kann gelöst werden” is correct, and it is heavy. Three verb forms to carry one idea. At C1, German usually reaches for something lighter — and in the places you meet this most, a Diskussion, a Radiokommentar, a Vortrag, that lightness is the whole point: you are asserting what is possible, and you want the claim, not the machinery.
The four, at a glance
| Form | German | Register |
|---|---|---|
| werden-passive | Das Problem kann gelöst werden. | neutral, but heavy |
| man | Man kann das Problem lösen. | everyday, spoken and written |
| sich lassen | Das Problem lässt sich lösen. | the C1 default in writing |
| -bar | Das Problem ist lösbar. | compact, almost a label |
| sein + zu | Das Problem ist zu lösen. | formal, official |
man — the plain one
man turns the sentence back into an active one with a vague subject. It is the least formal of the four and the easiest to reach for, which is exactly why it can weaken a written argument: it puts an invisible person back in the sentence you were trying to keep impersonal.
Man kann die Daten unterschiedlich lesen.
The data can be read in different ways.
active, with man as subject
Hier darf man nicht parken.
You mustn't park here.
man carries the modal naturally
Man hat mir nichts gesagt.
I wasn't told anything.
a neat way round a passive with a dative verb
sich lassen — the one your reading is full of
lassen + sich + infinitive means “can be done”. The thing itself becomes the subject, so the sentence stays impersonal like a passive, but reads far lighter. This is the construction C1 texts use most, and the infinitive is a plain infinitive — never a participle.
Die Daten lassen sich so lesen.
The data can be read that way.
= Die Daten können so gelesen werden
Der Weg lässt sich in Sekunden zurücklegen.
The distance can be covered in seconds.
separable verb, still a plain infinitive
Das lässt sich zum jetzigen Zeitpunkt nicht seriös beantworten.
That can't be answered responsibly at this point.
the hedge that C1 discussion writing runs on
-bar — when an adjective will do
Many transitive verbs form an adjective in -bar meaning “able to be …ed”: lösbar, machbar, essbar, erreichbar, vorstellbar. It is the most compact of the four and the only one that can sit in front of a noun. The catch is that it is lexical, not a rule — you cannot invent them freely, and a wrong one sounds instantly foreign.
Der Schaden ist reparierbar.
The damage is repairable.
= lässt sich reparieren
eine kaum vorstellbare Menge
a barely imaginable quantity
the one form that works attributively, before the noun
Der Termin ist nicht verschiebbar.
The appointment can't be moved.
negated with nicht, or with un-: unverschiebbar
Tipp · If you are not sure a -bar adjective exists, use sich lassen instead. “Das lässt sich besprechen” is always safe; “besprechbar” is the kind of word that gets you a red pen. Native writers hesitate here too — that is why sich lassen is the default.
sein + zu — the official one
sein + zu + infinitive is the register of notices, contracts and instructions. It carries a genuine ambiguity that the others do not: depending on context it means either “can be done” or “must be done”, and German simply lets context decide.
Die Rechnung ist bis Freitag zu bezahlen.
The invoice is to be paid by Friday.
obligation — must
Die Handschrift ist kaum zu lesen.
The handwriting is barely legible.
possibility — can. kaum/nicht usually signals this reading
Formulare sind vollständig auszufüllen.
Forms are to be filled in completely.
separable verb: zu goes inside — auszufüllen
Where each one cannot go
- man cannot be used when the doer is named. “Das Problem lässt sich von uns lösen” is fine; “Man kann es von uns lösen” is not — man IS the doer.
- sich lassen needs a genuine object to promote. It will not work on verbs that take no accusative object.
- -bar exists only for the verbs that happen to have it, and always means possibility — never obligation.
- sein + zu is ambiguous by design, so avoid it where the difference between can and must actually matters.
✗Das Problem lässt sich gelöst werden.
✓Das Problem lässt sich lösen.
sich lassen takes a plain infinitive. Adding werden + participle rebuilds the very passive you were replacing.
✗Man kann das Problem gelöst werden.
✓Man kann das Problem lösen.
man makes the sentence ACTIVE. Once you have man, the passive goes.
✗Der Vorschlag ist besprechbar.
✓Der Vorschlag lässt sich besprechen.
-bar is not productive — you cannot coin it at will. When in doubt, sich lassen.
✗Ich bin zu helfen.
✓Mir ist zu helfen. / Man kann mir helfen.
sein + zu needs the thing acted on as subject, and helfen takes the dative — so the person cannot be the nominative subject here either.
✗Die Daten lassen sich lesen werden.
✓Die Daten lassen sich lesen.
Same trap as the first, with a separable-looking tail. Nothing follows the infinitive.
None of these replaces the passive outright — “Die Entscheidung wurde gestern getroffen” has no lighter equivalent, because it reports a completed event rather than a possibility. Every form here is about what CAN (or must) be done. When you mean what happened, you still want werden; see the passive guide for that half of the picture.