Interrogative clauses form questions. There are two types of interrogative clauses, the yes-no questions and the question-word questions (w-word questions).
| Examples | |
| Besucht uns Patrick morgen? | yes-no question |
| Wann besucht uns Patrick morgen? | question-word (w-word) question |
With yes-no questions, we ask whether the fact stated in the question is true or false.
| Example |
| Besucht uns Patrick morgen? |
| Ist es wahr, dass Patrick uns morgen besucht? |
With question-word questions, we ask information about an unknown part of the fact stated in the question.
| Example |
| Wann besucht uns Patrick morgen? |
| Unknown fact component: the time of the visit |