không thể

Cannot

Level 2

Không thể means cannot or unable to. It is placed directly before a verb to show that an action is physically impossible or prevented by external circumstances.

How It Works

The basic structure is very simple and can be used with verbs, adjectives, and nouns:

1. With Verbs: Subject + không thể + Verb (+ Object)
You will frequently hear native speakers add the word được at the end of the sentence (không thể ... được). This is completely optional, but it adds emphasis and gives the sentence a natural rhythmic balance.

2. With Adjectives: Subject + không thể + Adjective
This is often used to express extreme states or comparisons, such as không thể tốt hơn (couldn't be better).

3. With Nouns: Subject + không thể là + Noun
When using không thể with a noun, you must include the copula là (to be). For example, Đó không thể là sự thật (That cannot be the truth).

4. As a Standalone Predicate: Subject + là + không thể
Không thể is frequently used all by itself meaning "impossible." Example: Chuyện đó là không thể! (That is impossible!).

Common Variations:

  • không thể nào + V: Adds strong emphasis, meaning "absolutely cannot" or "there is no way to".
  • không thể không + V: A double negative meaning "cannot help but" or "must".
  • chưa thể + V: Means "cannot yet". This is used when you currently lack the ability but expect to be able to do it in the future.

Crucial Distinctions for Learners:
Because English uses 'cannot' for several different concepts, learners often confuse không thể with other patterns. Keep these rules in mind:

  • Circumstantial Inability: Both không thể and không + V + được express physical or circumstantial inability (e.g., I cannot go because it is raining). However, không thể is more formal and common in writing, while không + V + được is the standard, natural choice for casual speech. When using không + V + được with a direct object, the object can go either before or after được (e.g., Tôi không ăn được thịt OR Tôi không ăn thịt được).
  • Lack of Learned Skill: Use không biết. (e.g., I cannot swim because I never learned how).
  • Prohibition: Use không được + V. (e.g., I cannot go because my boss forbade me).

Examples (4)

  1. Tôi không thể đến hôm nay.

    I cannot come today.

    Word by Word: I not able arrive today.

    A standard, neutral sentence showing that circumstances prevent the speaker from coming.

  2. Trời mưa to quá, chúng ta không thể đi chơi.

    It's raining too hard, we cannot go out.

    Word by Word: Sky rain big too, we not able go play.

    Clearly demonstrates an external circumstance (heavy rain) making the action impossible.

  3. Chân tôi bị đau nên tôi không thể chạy được.

    My leg hurts so I cannot run.

    Word by Word: Leg my suffer pain so I not able run get.

    Shows a physical limitation. Notice the optional 'được' at the end for emphasis and natural cadence.

  4. Tôi nghe tin nhắn mấy lần nhưng không thể hiểu anh ấy định nói gì.

    I listened to the message a couple of times but could not understand what he was trying to say.

    Word by Word: I hear message few time but not able understand he intend say what.

    Shows an absolute inability to comprehend the message despite having the means to listen to it.

Common Mistakes

  • Saying 'không có thể' instead of 'không thể'.

    Tôi không có thể đi.
    Tôi không thể đi.

    Because the affirmative word for 'can' is có thể, English speakers logically assume the negative is 'không có thể'. However, standard Vietnamese grammar dictates dropping the 'có', making it strictly không thể.

  • Using 'không thể' to express a lack of learned skill.

    Different MeaningTôi không thể nói tiếng Pháp.
    Tôi không biết nói tiếng Pháp.

    If you cannot do something because you never learned how (like speaking a language or playing the piano), không biết is the natural choice. Không thể says you are unable to, which fits when something stops you (e.g., you have a sore throat), so 'Tôi không thể nói tiếng Pháp' can sound like it is impossible for you.

How It Connects

Tap a pattern to see what it builds on and what it leads to.

không thểLevel 2Cannot

Learn This First

To understand 'không thể' (cannot), you first need to know how to express ability with 'có thể' and how to negate actions using 'không'. Since Vietnamese verbs do not conjugate, 'không thể' is simply placed before the main verb to indicate impossibility.

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Words in This Pattern

không thể