Why “He Runs Quick” Is Wrong — and How TOEIC Tests You on It

Learn the difference between words like fast and fastly, clear and clearly — and how TOEIC hides this grammar in Part 5 traps.

“He runs quick.”
It sounds fine.
You’ve probably said it.
But on TOEIC, it’s wrong. And they know most people don’t see why.

This is one of TOEIC’s favourite tricks. You’ll see a sentence that feels right… and fail if you pick the wrong word.

Let’s fix it — permanently.

1. What Are You Describing? A Thing or an Action?

Here’s the whole rule in one line:

  • If you're describing a thing, use words like quick, clear, calm

  • If you're describing an action, use words like quickly, clearly, calmly

That's it.

Forget “adjective” and “adverb.” You don’t need the terms. Just check what you're describing.

2. Wrong vs Right in Real Sentences

Let’s make it real:

  • She explained the rules clear → wrong

  • She explained the rules clearly → right (describes how she explained)

  • He answered polite → wrong

  • He answered politely → right

  • They worked efficient → wrong

  • They worked efficiently → right

  • I finished the task quick → wrong

  • I finished the task quickly → right

Each time, the sentence is describing how something was done. That's always going to need the -ly version.

3. What TOEIC Actually Throws at You

TOEIC loves to hide this mistake in plain sight. Example:

The manager handled the situation ______.

A) calm
B) calmly
C) calming
D) calmness

Answer: B) calmly.
Why? You're describing how the manager handled it. That’s an action. You need the -ly word.

4. These Word Pairs Catch Everyone

TOEIC will give you both versions and wait for you to mess it up.

Here are the common pairs:

You’ll see clear / clearly, quick / quickly, efficient / efficiently, polite / politely, correct / correctly, quiet / quietly, slow / slowly, and loud / loudly.

They’re used in almost every test — especially in Part 5. You’ll get a sentence with a verb like “speak,” “reply,” “complete,” or “explain,” and the wrong answer will look just as good as the right one… unless you know what to look for.

5. The Fastest Way to Get It Right

Just ask yourself this:

  • Are you talking about a thing? Then use clear, quick, efficient (no -ly).
    → “The report is clear.”
    → “It was a quick meeting.”
    → “The system is efficient.”

  • Are you talking about how someone does something? Then use clearly, quickly, efficiently.
    → “She explained it clearly.”
    → “He left quickly.”
    → “They worked efficiently.”

The words look similar, but the job they’re doing is totally different.

6. TOEIC's Favourite Trick: Fake -ly Words

Sometimes TOEIC gives you words that look like adverbs but aren’t what you think.

Here’s what they throw at you:

  • fast is already an adverb. Never say “fastly.”
    → “He runs fast.” = correct.

  • hard is fine as an adverb. Don’t say “hardly” unless you mean “almost not at all.”
    → “She works hard.” = good
    → “She hardly works.” = totally different meaning

  • late works both ways.
    → “A late train” = adjective
    → “He arrived late” = adverb

TOEIC will give you the wrong version — and hope you panic and grab it.

7. Let’s Practice (TOEIC Style)

Try these.

Q1: The engineer responded to the issue ______.
A) quick
B) quickly
Answer: quickly — it’s describing an action.

Q2: The instructions were ______ and easy to understand.
A) clear
B) clearly
Answer: clear — you’re describing the instructions themselves.

Q3: The new intern completed the task ______.
A) efficient
B) efficiently
Answer: efficiently — describing how the task was done.

Final Check Before the Test

If you're ever unsure, stop and ask:

“Is this talking about what something is?”
→ Use the plain form. (calm, quick, clear)

“Is this talking about how something is done?”
→ Use the -ly version. (calmly, quickly, clearly)

You don’t need to memorise grammar terms.
You just need to train your eyes to see what the sentence is doing.

TOEIC is counting on you rushing.
Slow down, check the job of the word — and get it right every time.

FAQ (EN) — Why “He Runs Quick” Is Wrong 1. Q: Why is “He runs quick” wrong? A: Because “runs” is an action. You need an adverb to describe it. The correct sentence is “He runs quickly.” 2. Q: What’s the difference between “quick” and “quickly”? A: “Quick” describes a thing (e.g., a quick meeting). “Quickly” describes an action (e.g., leave quickly). 3. Q: When do I use words ending in “-ly”? A: Use “-ly” words when describing how something is done. Example: “She answered clearly.” 4. Q: Can I say “She speaks fluent English”? A: No. You should say “She speaks fluently” or “She is fluent in English.” 5. Q: Why is “He answered correct” wrong? A: “Answered” is an action. You need an adverb: “He answered correctly.” 6. Q: Is “fastly” a real word? A: No. “Fast” is both an adjective and adverb. Use “He runs fast,” not “fastly.” 7. Q: What does TOEIC test with words like “clear” and “clearly”? A: TOEIC tests whether you know when to describe a thing (use “clear”) or an action (use “clearly”). 8. Q: Is “He explained it polite” correct? A: No. You need the adverb: “He explained it politely.” 9. Q: Why does TOEIC use “efficient” and “efficiently” in questions? A: To test if you recognize whether the sentence describes a method (action = “efficiently”) or quality (thing = “efficient”). 10. Q: How do I choose between “quiet” and “quietly”? A: “Quiet” describes something (e.g., a quiet room). “Quietly” describes how something is done (e.g., speak quietly). 11. Q: Can “hard” be used like an adverb? A: Yes. “She works hard” is correct. “Hardly” means “almost not at all,” which is different. 12. Q: What’s the difference between “late” and “lately”? A: “Late” means after the expected time. “Lately” means “recently.” Example: “He arrived late.” vs. “Lately, he’s been tired.” 13. Q: Why do I get confused by “clear” and “clearly”? A: Because they both look similar. Remember: use “clearly” when describing actions like speaking or explaining. 14. Q: Is “The teacher speaks calm” okay? A: No. It should be “The teacher speaks calmly.” 15. Q: Can I say “The report is clearly”? A: No. That’s describing the report, not an action. Use “The report is clear.” 16. Q: What does “She smiled polite” mean? A: It’s incorrect. Use “She smiled politely” to describe how she smiled. 17. Q: How can I tell if I need an adjective or adverb in TOEIC? A: Look at what’s being described. If it’s an action, use the “-ly” adverb form. 18. Q: Is “The device works good” wrong? A: Yes. The correct phrase is “The device works well.” “Well” is the adverb of “good.” 19. Q: Why does TOEIC include fake words like “fastly”? A: To trick you. “Fastly” looks right, but it’s wrong. “Fast” is already correct as an adverb. 20. Q: What’s the fastest way to check if I picked the right word? A: Ask yourself: “Is this describing how something is done?” If yes, use the adverb with “-ly.”