Introduction

In English, there are two types of open-ended questions:

Subject questions → Ask about who or what performs an action.

Object questions → Ask about who or what is affected by the action.

Open-ended questions are formed using question words (who, what, where, etc.).

Object Questions: Asking About the Object

Object questions ask about the person or thing affected by an action. These questions follow inversion, meaning the verb comes before the subject.

Examples of Inversion:

He is a doctor. (statement)
Is he a doctor? (question with inversion)

As you can see, we inverted (moved to the first position) the verb “to be”. We invert “to be”, the main verb or the auxiliary verb.

She baked cookies. (statement)
Did she bake cookies? (question with inversion using “did” in Past Simple)

He will fix my car. (statement)
Will he fix my car? (question with inversion using “will” in Future Simple)

To form an object question, we place a question word before the inverted verb.

What did she bake? (instead of “She baked what?”)

What will he give you? (instead of “He will give you what?”)

Subject Questions: Asking About the Subject

Subject questions ask who or what is performing an action. Unlike object questions, they do not use inversion—the sentence follows a normal statement structure.

He is a teacher. (statement)
Who is a teacher? (subject question, no inversion)

To form a subject question, we replace the subject of the sentence with who or what.

Who likes oranges?
(instead of “Who does like oranges?”)

What is making that noise?
(instead of “What does make that noise?”)

Unlike object questions, do/does/did is not used in subject questions.

Where does she work?
(object question)

Who works here?
(subject question, no “does”)

Who does work here?

Sentence Structure in English

Subject = The person or thing performing the action.

Object = The person or thing affected by the action.

Emma likes coffee.

Emma is the subject (she is doing the action).

Coffee is the object (it is being liked).

We are building a new house.

We = subject

Are building = verb

A new house = object

Some verbs (intransitive verbs) do not take an object.

Anna slept.
(no object needed)

The phone rang.
(no object needed)

Subject vs. Object Questions: Comparisons

Present Tenses

Present Simple

The class starts at 10 a.m. (statement)
➡ What starts at 10 a.m.? (subject question)
➡ When does the class start? (object question)

Present Continuous

The dog is chasing a cat.
➡ Who is chasing a cat? (subject question)
➡ What is the dog chasing? (object question)

Present Perfect

Sophie has written a novel.
➡ Who has written a novel? (subject question)
➡ What has Sophie written? (object question)

Present Perfect Continuous

I have been studying French.
➡ Who has been studying French? (subject question)
➡ What have I been studying? (object question)

Past Tenses

Past Simple

Liam ate a sandwich.
➡ Who ate a sandwich? (subject question)
➡ What did Liam eat? (object question)

Past Continuous

Sarah was watching a movie.
➡ Who was watching a movie? (subject question)
➡ What was Sarah watching? (object question)

Past Perfect

Tom had visited his grandparents before.
➡ Who had visited his grandparents before? (subject question)
➡ Whom had Tom visited before? (object question)

Past Perfect Continuous

They had been playing chess for an hour.
➡ Who had been playing chess? (subject question)
➡ What had they been playing? (object question)

Future Tenses

Future Simple

Mia will buy a new phone.
➡ Who will buy a new phone? (subject question)
➡ What will Mia buy? (object question)

Future Continuous

We will be traveling next week.
➡ Who will be traveling next week? (subject question)
➡ When will we be traveling? (object question)

Future Perfect

Emma will have finished her project by Friday.
➡ Who will have finished her project by Friday? (subject question)
➡ What will Emma have finished by Friday? (object question)

Future Perfect Continuous

She will have been teaching for five years.
➡ Who will have been teaching for five years? (subject question)
➡ How long will she have been teaching? (object question)

Tense	Statement	Subject question	Object question
Present Simple	Tom writes a book.	Who writes a book?	What does Emma write?
Present Continuous	Tom is writing a book.	Who is writing a book?	What is Emma writing?
Present Perfect	Tom has written a book.	Who has written a book?	What has Emma written?
Present Perfect Continuous	Tom has been writing a book.	Who has been writing a book?	What has Emma been writing?
Past Simple	Tom wrote a book.	Who wrote a book?	What did Emma write?
Past Continuous	Tom was writing a book.	Who was writing a book?	What was Emma writing?
Past Perfect	Tom had written a book.	Who had written a book?	What had Emma written?
Past Perfect Continuous	Tom had been writing a book.	Who had been writing a book?	What had Emma been writing?
Future Simple	Tom will write a book.	Who will write a book?	What will Emma write?
Future Continuous	Tom will be writing a book.	Who will be writing a book?	What will Emma be writing?
Future Perfect	Tom will have written a book.	Who will have written a book?	What will Emma have written?
Future Perfect Continuous	Tom will have been writing a book.	Who will have been writing a book?	What will Emma have been writing?

Subject and object questions

Introduction

Object Questions: Asking About the Object

Subject Questions: Asking About the Subject

Sentence Structure in English