dass-clauses and their equivalents

A dass-clause is a subordinate clause introduced by the conjunction dass that functions as the subject or object of the main clause (e.g. Ich hoffe, dass ich dich bald wiedersehe.). German offers three main alternatives: a zu-infinitive construction (when both clauses share the same subject), a nominal phrase (a noun group replacing the entire clause), and a correlate — a pronoun such as es or a da(r)+preposition form such as darauf that sits in the main clause and points forward to the dass-clause. Choosing the right alternative depends on the verb, the subjects involved, and the register.

• zu-infinitive — identical subjects only. When the subject of the main clause and the subject of the dass-clause are the same person or thing, the dass-clause can — and often should — be replaced by a zu-infinitive. The subordinate subject is dropped and the verb becomes infinitive with zu: Ich hoffe, dass ich dich bald wiedersehe. → Ich hoffe, dich bald wiederzusehen.

• dass-clause — different subjects. When the subjects differ, the dass-clause is obligatory and cannot be replaced by a zu-infinitive: Wir freuen uns, dass ihr uns besucht. (We are glad that you are visiting us — two different subjects.)

• Nominal phrase — concise, formal register. Both a dass-clause and a zu-infinitive can often be compressed into a noun phrase, especially in written German: Ich hoffe auf eine baldige Antwort. The preposition used with the noun phrase is the same as the one required by the verb.

• Correlates — obligatory or optional anticipatory pronouns. Some verbs require a correlate in the main clause when a dass-clause follows. Verbs that govern a preposition use a da(r)+preposition form (darauf, damit, daran …); verbs without a preposition may use es. For example, sich freuen auf requires darauf: Wir freuen uns darauf, dass ihr uns besucht.

The table below shows how the same idea is expressed in each of the three forms. The verb used throughout is hoffen auf (to hope for).

Forming the zu-infinitive. For simple verbs, place zu directly before the infinitive: zu sehen. For separable verbs, zu is inserted between the prefix and the stem, written as one word: wieder·zu·sehen → wiederzusehen. Modal verbs do not take zu and cannot head a zu-infinitive construction.

Forming the correlate. Identify the preposition the verb requires, then prefix da- (or dar- before a vowel): auf → darauf, mit → damit, an → daran. The correlate occupies its normal position in the main clause; the dass-clause (or zu-infinitive) follows after the comma.

• Mixing dass and zu-infinitive in one clause.

  ✗ Ich hoffe, dass ich dich bald wiederzusehen.

  ✓ Ich hoffe, dich bald wiederzusehen. (zu-infinitive, no dass)

  ✓ Ich hoffe, dass ich dich bald wiedersehe. (dass-clause, finite verb)

  The conjunction dass and the zu-infinitive are mutually exclusive. Use one or the other, never both.

• Dropping an obligatory correlate.

  ✗ Wir freuen uns, dass ihr uns besucht.

  ✓ Wir freuen uns darauf, dass ihr uns besucht.

  Verbs that govern a preposition (e.g. sich freuen auf, warten auf, achten auf) require the matching da(r)+preposition correlate in the main clause whenever a dass-clause or zu-infinitive follows. Omitting it produces an ungrammatical sentence.

• Using the zu-infinitive when the subjects differ.

  ✗ Ich hoffe, du bald wiederzusehen.

  ✓ Ich hoffe, dass du bald kommst.

  The zu-infinitive is only valid when both clauses share the same subject. If the subjects are different, a full dass-clause with a finite verb is required.