Subject vs. Object Questions
Do you know the difference between "Who called you?" and "Who did you call?" In English, when the question word (like who or what) is the subject of the sentence, we don't use auxiliary verbs like do, does, or did. For example, "Who ate the sandwich?" However, when asking about the object, we need the auxiliary verb: "What did you put in the microwave?"
This challenge will help you master both question structures. You will navigate through fun, practical scenarios to determine whether you are asking about the doer of an action or the receiver. The exercises cover situations ranging from finding out who stole a cake and interrogating suspects like a detective, to digging into roommate drama, blind dates, and office gossip.
You will work through 12 questions using a mix of single-choice, multi-choice, and drag-and-drop formats.
Try the quiz to check your knowledge!
Correct Answers
Complete the gossipy text message with the correct question format.
I heard Sarah went on a blind date yesterday, but she won't tell me anything! Who ___?
The correct answer is did she meet.
This is an object question. You are asking about the object of the verb (the person Sarah met), while Sarah is the subject.
For object questions in the past simple, we must use the auxiliary verb did followed by the subject and the base verb: Question Word + did + subject + base verb (Who did she meet?).
Help the amateur detective interrogate the suspects by choosing the grammatically correct question.
The detective pointed dramatically at the empty cake stand. "Alright, confess! Who ___ my double-chocolate masterpiece?"
The correct answer is ate.
When the question word (like "Who" or "What") is the subject of the sentence, we do not use the auxiliary verbs do, does, or did. We simply use the normal affirmative word order: Who + verb.
"Who did eat" is incorrect because we only use did in object questions or for special emphasis, and "did ate" is grammatically incorrect because did must be followed by a base verb.
The correct answers are Who threw away my favorite coffee mug? and What did the landlord say about the noise?
Who threw away... is a subject question. Because "Who" is performing the action, we don't use did.
What did the landlord say... is an object question. Because "the landlord" is the subject performing the action, we need the auxiliary verb did to form the question.
"Who did break..." is incorrect because it incorrectly uses an auxiliary verb in a subject question. "What you put..." is incorrect because it is missing the auxiliary verb did for an object question.
caused did you download
Subject vs. Object Questions:
In the first sentence, "What" acts as the subject (the thing causing the fire), so no auxiliary did is needed. We just use the past tense verb: What caused...
In the second sentence, "you" is the subject doing the downloading, making "which mysterious file" the object. Because we are asking about the object, we need the auxiliary verb did before the subject: ...did you download?
Complete the roommates' argument about the kitchen disaster by dragging the correct phrases into the blanks.
"Okay, I'm not mad, I just want to understand. What exactly happened to our poor microwave?"
"And what on earth did you put inside it that caused this massive explosion?"
"What exactly happened to our poor microwave?"
This is a subject question. "What" acts as the subject (the thing that happened). In past simple subject questions, we use the past tense verb directly ("happened") without the auxiliary "did."
"And what on earth did you put inside it that caused this massive explosion?"
This is an object question. "You" is the subject performing the action, and "what" is the object being placed in the microwave. Therefore, we use the auxiliary verb "did" (Question Word + did + Subject + Base Verb).
rescued did the prince betray
Subject vs. Object Questions:
When "Who" asks about the subject (the person doing the rescuing), we use the normal verb form without an auxiliary: Who rescued...
When "Who" asks about the object (the person receiving the betrayal), we use an auxiliary verb (did) before the subject (the prince): Who did the prince betray...
Piece together the office gossip's dramatic retelling of the stolen sandwich incident by dragging the correct words to the gaps.
"We have a lunch thief on the loose! Which coworker stole the boss's legendary turkey sandwich?"
"Wait, there were two identical turkey sandwiches in the fridge! Which one did they take?"
"Which coworker stole the boss's legendary turkey sandwich?"
This is a subject question. The phrase "Which coworker" is the subject doing the stealing. We use the past tense verb ("stole") directly, with no auxiliary verb.
"Which one did they take?"
This is an object question. The subject is "they" (the thief), and "Which one" is the object being taken. Because we are asking about the object, we need the auxiliary verb "did" before the subject.
The correct answers are Who does Sarah like from the soccer team? and Who invited the math teacher to the prom?
Who does Sarah like... asks about the object (the person Sarah likes). Since Sarah is the subject, we need the auxiliary verb does.
Who invited... asks about the subject (the person who did the inviting). Therefore, we follow normal statement word order and do not use did.
Choose the question that correctly asks who performed the action of inviting the strange guest.
A guy in a full dinosaur suit just walked into your living room. Since you definitely didn't invite him to the party, you turn to your roommate and ask: "___"
The correct answer is Who invited the dinosaur?.
You need a subject question because you want to know the identity of the person who performed the action (the subject). Therefore, you drop the auxiliary verb did and put the main verb in the past tense: "Who invited the dinosaur?"
"Who did the dinosaur invite?" is a perfectly formed object question, but it asks the wrong thing! It asks which lucky person received an invitation from the dinosaur.
ate did you leave
Subject vs. Object Questions:
In the first question, "Who" is the subject (the person performing the action of eating). When the question word is the subject, we do not use the auxiliary verb did. We just use the past tense verb: Who ate...?
In the second question, "what" is the object (the thing being left), and "you" is the subject. When asking about the object, we must use the auxiliary verb did before the subject: What did you leave...?
The correct answers are Who ate the last slice of chocolate cake? and Who did the suspect call before fleeing?
When the question word (like "Who" or "What") is the subject of the sentence, we do not use an auxiliary verb like do, does, or did. We just use the normal verb (e.g., "Who ate...").
When the question word is the object of the sentence, we must use an auxiliary verb before the subject (e.g., "Who did the suspect call...").
Help Detective Miller complete his interrogation notes by dragging the correct verbs into the blanks.
"Let's get straight to the facts. First, tell me: who calls you every night exactly at midnight?"
"And more importantly, who do you call when you desperately need an alibi?"
"First, tell me: who calls you every night exactly at midnight?"
This is a subject question. The question word "who" is the subject performing the action (calling). In present simple subject questions, we use the normal affirmative verb form ("calls") without an auxiliary verb (do/does).
"And more importantly, who do you call when you desperately need an alibi?"
This is an object question. The subject of the sentence is "you," and "who" is the object receiving the action. We must use the auxiliary verb "do" (Question Word + do/does + Subject + Base Verb).
Questions
- ✅ Do you like coffee? — do-support (no existing auxiliary)
- ✅ Can she swim? — inversion (auxiliary before subject)
- ✅ Where does he live? — wh-question
- ✅ You're coming, aren't you? — tag question
Questions require inversion (auxiliary before subject) or do-support (add do/does/did). Types: yes/no (Do you…?), wh- (What/Where/When…?), negative (Don't you…?), tag (…isn't it?).
Rule: find the auxiliary. Move it before the subject. No auxiliary? Add do/does/did. Never use just intonation in written English (You like coffee? is not standard).
Subject
- ✅ The list of items is wrong. — subject = list (singular), not items
- ❌ The list of items are wrong. — trapped by nearest noun
- ✅ Running is good exercise. — gerund as subject
- ✅ What he said surprised me. — clause as subject
The subject is the noun/pronoun/phrase before the verb that controls its number and person. Finding the true subject — especially through prepositional phrases — is the key to subject-verb agreement.
Rule: strip away prepositional phrases between subject and verb. Whatever's left is the true subject. The list (of items) is wrong.
Object
- Sam fed the dogs. — direct object (what was fed)
- She sent him a present. — indirect object (who received it)
- She waited for Lucy. — prepositional object (after preposition)
- I gave her a book. — indirect + direct object together
An object is what a verb acts on or directs its action toward. Direct = the thing affected. Indirect = the recipient. Prepositional = after a preposition.
Test: Verb + what/whom? = direct object. Verb + to/for whom? = indirect object. After a preposition? = prepositional object.
English Grammar Basics
- She is a teacher. — verb be + noun complement
- He runs every day. — present simple, third-person -s
- They don't like coffee. — negation with do-support
- I have two cats. — possession, countable noun, no article before plurals
These sentences demonstrate English Grammar Basics — the foundational patterns every other topic builds on: parts of speech, basic tenses, articles, and simple sentence structure.
If you can identify the verb, the subject, and count the noun correctly, you've nailed the basics that make everything else click.
A2 | Elementary | Pre-intermediate
- ✅ I went to the cinema yesterday. — past simple
- ✅ I have visited Paris twice. — present perfect (life experience)
- ✅ If it rains, I'll take an umbrella. — first conditional
- ✅ You should see a doctor. — modal for advice
These patterns are A2 — the second CEFR level. At A2 you move past survival phrases into real grammar: past tenses, the present perfect, basic conditionals, and modals for advice/obligation.
Marker: if you can describe yesterday and give simple advice, but struggle with abstractions or nuance, you're at A2.
Medium
- If I were you, I would apologise. — one rule (second conditional), but distractors like was tempt you
- Answers require active thought, not instant pattern recognition
- Vocabulary and context are realistic, not artificially simplified
- Usually tests one rule, but the wrong answers are plausible
Medium marks middle-difficulty challenges: A2–B1, one rule tested, but with realistic distractors that require genuine understanding.
Use "Medium" when Easy feels too obvious but Hard feels overwhelming. This is where most productive learning happens — the sweet spot of difficulty.