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Substitution with So, Not, and Do: correct answers

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Substitution with So, Not, and Do

Instead of repeating entire clauses or verb phrases, advanced English speakers use substitution to keep their sentences concise and natural. For example, rather than replying "I think she will win," you can simply say "I think so." Similarly, to express a negative expectation, you might say "I hope not" instead of "I hope she does not win."

This challenge explores the nuanced rules of clause substitution and ellipsis. You will practice negative transfer with mental verbs (knowing when to use "I suspect not" versus "I don't think so"), adjective substitution (like using "remain so"), and verb phrase fronting ("and so I did" vs. "I did so"). You will also navigate tricky distinctions involving stative verbs with "do" and the correct usage of "say" vs. "tell" with "so."

You'll work through 10 questions featuring a mix of single-choice, multi-choice, drop-down, and drag-and-drop formats.

Try the quiz to check your knowledge!

HardC1 | AdvancedC1AdjectiveAdverbAuxiliary verbClauseComplementConditional sentenceIndirect speechInversionNegationObjectPast tensePhrasePresent tensePronounSentenceVerbVerb tenseSimple tenseWord order

Correct answers

Question 1

Two paranoid office workers are arguing. Select ALL the grammatically correct phrases to complete the classic "I was right!" moment.
"I warned you that the new coffee machine was sentient and plotting against us. I _____!"

The correct answers are told you so, said so, and did say so.

When using "so" to substitute for a reported clause, the verbs say and tell follow their usual grammar rules:

  • Tell requires an indirect object before "so" (I told you so). "I told so" is incorrect.
  • Say does not take an indirect object in this way (I said so or the emphatic I did say so). "I said you so" is incorrect.

Question 2

Select the grammatically correct option to complete the rival's statement.

"He claims to understand the complex rules of 4D quantum chess, but I highly doubt he actually _____."

The correct answer is does.

This question tests the restriction on the substitution phrase do so. We use "do so" (or "do it") to replace an action (dynamic verb). However, we cannot use "do so" or "do it" to substitute for a state (stative verbs like understand, know, like, or own).

Instead, we must use standard ellipsis, leaving only the auxiliary verb does to stand in for "understands the complex rules."

Question 3

Help the pretentious food critic finish his scathing review of a new avant-garde restaurant by selecting the correct substitutions.
The appetizers arrived completely frozen, and _________________________ the supposedly warm bread rolls. The head chef clearly despises the restaurant's owner, and after tasting the soup, I assure you, I _________________________. The manager begged me to leave a five-star rating to save their reputation, but as a culinary professional, I absolutely refused to _________________________.

The correct answers are so did, do too, and do so.

To agree with an affirmative statement, we use so + auxiliary + subject. The correct auxiliary for the past tense verb arrived is did.

We use the auxiliary do (or do too) to avoid repeating a verb phrase. We cannot use do so here because despise is a stative verb (a state of mind/feeling), and do so can only be used to replace dynamic (action) verbs.

Do so is used in formal contexts to replace an action verb and its objects (leave a five-star rating). Do it so and make so are incorrect grammatical combinations.

Question 4

Help the exasperated detective complete the transcript of this highly unusual interrogation by choosing the correct substitution word for each blank.

"Did the raccoon steal the mayor's toupee?" asked the detective. "I suppose so," replied the witness.

"Did you tell the creature to drop the hairpiece?" "I did, but it refused to do so and simply hissed at me."

"Will the mayor ever recover his dignity?" "I strongly suspect not."

"I suppose so," replied the witness.

We use so after verbs of thinking or speaking (like suppose, think, hope, say) to substitute for an entire affirmative clause. Here, it replaces "that the raccoon stole the toupee."

"I did, but it refused to do so..."

The auxiliary did is used for ellipsis to avoid repeating "told the creature to drop the hairpiece."

The formal phrase do so substitutes for the verb phrase "drop the hairpiece."

"I strongly suspect not."

We use not after verbs of thinking to substitute for a negative clause. Here, it means "I strongly suspect that he will not recover his dignity."

Question 5

Choose the correct word to complete the royal advisor's warning.

"The dragon is currently asleep and peaceful, but it will only remain _____ if you stop playing those dreadful bagpipes!"

The correct answer is so.

The word so can act as a substitute for an adjective or an adjective phrase functioning as a subject complement (in this case, "asleep and peaceful"). It frequently follows linking verbs like remain, seem, appear, and become.

Such is generally used to substitute for noun phrases, not adjective phrases, making "remain such" incorrect in this context.

Question 6

Help the gloomy scientist predict the future! Select ALL the responses that are grammatically correct and natural ways to express a negative expectation using substitution.
"Will the time machine be fixed by Tuesday?"

The correct answers are I hope not, I don't think so, and I guess not.

When substituting a negative that-clause, English verbs behave in two different ways:

  1. Negative transfer: Verbs like think, believe, and suppose usually make the main verb negative and use "so" (e.g., "I don't think so").
  1. Direct negative: Verbs like hope and guess keep the main verb affirmative and use "not" for the substitute clause (e.g., "I hope not"). "I don't hope so" is grammatically incorrect!

Question 7

Help the exhausted film director complete her frantic text messages to the producer by choosing the correct substitution words.
Director: "Is the lead actor going to storm out of his trailer again today?" Producer: "I suppose _________________________. He was complaining about the coffee."
Director: "Have they fixed the spaceship's lighting yet?" Producer: "I _________________________. The electrician just left for an extended lunch."
Director: "Are we going to go over budget on this scene?" Producer: "I desperately _________________________! The studio will definitely cancel us."

The correct answers are so, doubt it, and hope not.

After verbs of thinking and believing (like suppose, guess, think, assume), we use so to substitute for an entire that-clause.

The verb doubt is an exception. It does not take so; instead, it takes it to refer back to a previous clause or idea.

With the verb hope, the negative substitution is formed by using hope not. Making the main verb negative (I don't hope so) is grammatically incorrect in English.

Question 8

Choose the correct phrase to complete the podcast host's nervous response.

"Are the aliens going to beam up our broadcasting tower before we finish the episode?" asked the co-host. "I _____, or we'll never get our sponsorship money!"

The correct answer is strongly suspect not.

In English, when substituting a negative that-clause, verbs of thinking or believing are divided into two groups.

Verbs like think, believe, and suppose usually negate the main verb and use so (e.g., "I don't think so").

However, verbs like suspect, hope, assume, and be afraid keep the main verb affirmative and use not to replace the negative clause (e.g., "I hope not," "I suspect not"). Therefore, "don't suspect so" is grammatically unnatural here.

Question 9

Complete the amateur baker's dramatic blog post. Select ALL the options that correctly mean "and I followed that instruction" (rather than "and I also did it").
"The ancient, mystical recipe instructed me to knead the dough for exactly three hours, and _____."

The correct answers are so I did, I did so, and I did it.

"I did so," "so I did," and "I did it" all successfully substitute for the previously mentioned verb phrase (knead the dough for exactly three hours).

Watch out for "so did I"! Because of the inverted word order (verb before subject), it means "I also did this," which would imply someone else kneaded the dough first.

Question 10

Complete the spaceship captain's dramatic audio log by choosing the correct substitution word for each blank.

"The aliens may attempt to board the ship. If so, we must initiate the lockdown sequence immediately."

"Have they breached the outer hull yet? I believe not, but our sensors are severely damaged."

"We need to reroute power to the shields. Anyone who fails to do so will face a swift court-martial."

"I ordered the pilot to evade their lasers, and she did with surprising enthusiasm."

"If so, we must initiate the lockdown sequence immediately."

If so is a common C1 substitution phrase that replaces an entire affirmative conditional clause. Here, it stands for "If they attempt to board the ship."

"I believe not, but our sensors are severely damaged."

Not substitutes for the negative clause "that they have not breached the hull."

"Anyone who fails to do so will face a swift court-martial."

Do so is a formal way to substitute for a previously mentioned verb phrase—in this case, "reroute power to the shields."

"...and she did with surprising enthusiasm."

The auxiliary verb did is used here to stand in for the past tense verb phrase "evaded their lasers," avoiding unnecessary repetition.

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