In the simple present and simple past tense, we make questions and negatives with do, does and did. But there are some exceptions to this rule.
In subject questions where we want to find information about the subject, we do not use the auxiliary verb do/does/did.
In object questions where we want to find information about the object, we use the auxiliary verb do/does/did.
Study the sentence given below.
- John broke a window.
This sentence has a subject (John), a verb (broke) and an object (window).
Now when we make questions to find this information, there are two possibilities.
If we want to make a question where the answer is ‘window’, the question would be: What did John break? John broke a window.
Now if we want to make a question where the answer is ‘John’, the question would be ‘Who broke the window?’ ‘John broke the window.’
When we make a question where the answer is the object, we use the auxiliary do/did. In subject questions, the auxiliary do is not used.
More examples are given below.
Jack likes ice-cream. (Subject – Jack, verb – likes, object – ice-cream)
Subject question
Who likes ice-cream? Jack likes ice-cream. (NOT Who does like ice-cream?)
Object question
What does Jack like? Jack likes ice-cream. (NOT What Jack likes?)
My sister writes short stories.
Subject question
Who writes short stories? My sister writes short stories.
Object question
What does my sister write? My sister writes short stories.
Mary keeps a pig in the yard.
Subject question
Who keeps a pig in the yard? Mary
Object question
What does Mary keep in the yard? A pig