Object and subject questions

When we make questions in the past and present simple, we normally use an auxiliary verb:

'What time did you post the letter?'

When the question word (what?, who?, which?, how many'?) is the subject of the verb in the question, we do not use an auxiliary verb and the verb is in the third person.

'Who wrote 'Hamlet'?'

You'll find more examples here.

Activity 1: Choose the correct answer.
Activity 2: Complete the sentences.
Activity 3: Make object or subject questions.