Lesson

Who saw you? Who did you see?

Subject vs object questions

≈ 15 min 8 block(s)

Text

Who saw you? Who did you see?

This lesson explains the difference between subject questions and object questions in the past simple. 'Who' can ask about the subject (the person who performed the action) or about the object (the person who received the action). The form changes depending on whether 'who' is the subject or the object.

  • Subject question (Who + past verb): 'Who saw you?' → asking who did the seeing.
  • Object question (Who + did + subject + base verb): 'Who did you see?' → asking who was seen by you.
  • Remember: use the past verb directly for subject questions; use 'did' + base verb for object questions.

Table

Subject vs Object Questions (Past Simple)

Question Type Form Example
Subject question Who + past verb (no auxiliary) Who saw you?
Object question Who + did + subject + base verb Who did you see?
Subject example Who + past verb Who invited the client to the meeting?
Object example Who + did + subject + base verb Who did they invite to the meeting?

Tip

Key rule: Subject vs Object in past questions

Decide whether 'who' is the subject (does the action) or the object (receives the action). Form the question accordingly.

  • If 'who' is the subject: use Who + past verb. Example: Who organized the event?
  • If 'who' is the object: use Who + did + subject + base verb. Example: Who did you invite?
  • After 'did', always use the base form of the verb (not the past tense).

Ask: Who did it? → subject question. Who did you call? → object question (use 'did').

Example

Examples in context

Who saw you at the conference?

Who did you see at the conference?

Who invited the client to the meeting?

Who did you invite to the meeting?

Tip

Common mistakes to avoid

Learners often mix forms when forming past simple questions with 'who'. Watch for these universal errors.

  • Using 'did' with a past tense verb: 'Who did saw you?' is incorrect.
  • Using past tense after 'did': 'Who did you saw?' → after 'did' use the base form ('see').
  • Confusing subject and object roles and thus using the wrong word order.
  • Incorrect word order in questions: placing the subject and auxiliary incorrectly.

Focus on subject vs object and the verb form after 'did'.

Quiz

Choose the correct sentence for asking about the subject in the past:

Hint: Focus on whether 'who' performs the action (subject) or receives it (object).

Quiz

Complete: _____ you see at the meeting?

Hint: Think about past simple object questions and use auxiliary + base verb.

Quiz

Choose the correct way to ask about the person Mark invited last week:

Hint: Check word order for past object questions: question word + auxiliary + subject + base verb.

Key Points

Vocabulary

who

pronoun CEFR A1 //huː//

used to ask about people (subject or object)

Who called the client?

GrammarPoint

did

auxiliary verb CEFR A2 //dɪd//

past simple auxiliary used to form questions and negatives

Did you finish the report?

GrammarPoint

past simple

grammar CEFR B1 //pɑːst ˈsɪmpəl//

a tense to describe actions completed in the past

The team completed the project last month.

GrammarPoint

subject question

grammar CEFR B1 //ˈsʌbdʒɛkt ˈkwɛs.tʃən//

a question where the question word is the subject performing the action

Who signed the contract?

GrammarPoint

object question

grammar CEFR B1 //ˈɒbdʒɛkt ˈkwɛs.tʃən//

a question where the question word asks about the object that receives the action

Who did you call after the meeting?

GrammarPoint

base form

grammar CEFR A2 //beɪs fɔːm//

the infinitive form of a verb without 'to' (for example: 'see', 'invite')

After 'did', use the base form: 'did see', not 'did saw'.