What are direct and indirect questions?
A direct question is a question that starts with a question word: what, who, where, why, when, how. An 'indirect question' is a direct question inside a statement.
- Direct question: "What time is it?"
- → Indirect question: "Do you know what time it is?"
When speaking, indirect questions are usually more polite or formal than direct questions.
How do we form indirect questions?
1. With the verb 'be': Switch the subject and 'be' verb:
- What time is it?
- → Do you know what time it is?
2. With do/does/did: Do not switch the subject and verb. Simply remove 'do/does/did'.
Remember to change the main verb accordingly: add an -s to the main verb when you remove 'does' and change the main verb to the past tense when you remove 'did'.
- Where do they live?
- → Do you know where they live?
- [= not "Do you know where 'do' they live?"]
- Where does she live?
- → Do you know where she lives?
- [= not "Do you know where 'does' she live?"]
- Where did she live?
- → Do you know where she lived?
- [= not "Do you know where 'did' she live?"]
3. With other helping verbs: When a direct question has a helping verb other than 'do/does/did', switch the subject and the helping verb.
- Where can I find that book?
- → Do you know where I can find that book?
4. With a question word subject: When the subject of a direct question is a question word/phrase (who, what, what time), the word order does not change.
- Who runs fastest?
- → Do you know who runs fastest?
5. With yes-no questions: Use 'if' after the question markers ('do you know'). Then change the verb appropriately (for instance, make it past tense if you took out 'did').
- Did she study for the exam?
- → Do you know if she studied for the exam?