Negatives with Modal Verbs
To make a sentence containing a modal verb negative, we add the negative particle not immediately after the modal verb and before the main verb.
Formula: Subject + Modal Verb + not + Verb 1 (Base Form) + ...
1. The Unique Spelling of “Cannot”
Unlike other modals where the modal and not are written as two separate words (e.g., should not, will not), the negative form of can is written as one single word: cannot.
- Correct: I cannot swim.
- Incorrect: I can not swim. (Except when “not” belongs to a different structure like “not only… but also”).
2. Modal Negation and Contractions
In spoken English, negative modals are almost always contracted. Here is the list of common modals and their negative forms:
| Modal Verb | Full Negative Form | Contracted Form | Example |
|---|---|---|---|
| can | cannot | can’t | I can’t hear you. |
| could | could not | couldn’t | We couldn’t find the key. |
| should | should not | shouldn’t | You shouldn’t eat that. |
| must | must not | mustn’t | You mustn’t touch that. |
| will | will not | won’t | He won’t agree to this. |
| would | would not | wouldn’t | She wouldn’t open the door. |
| might | might not | mightn’t | It mightn’t rain after all. |
| may | may not | (no contraction) | You may not park here. |
3. Negatives with Modal Perfects
To talk about a negative possibility, obligation, or regret in the past, we use a modal perfect structure. We place not immediately after the modal verb.
Formula: Subject + Modal + not + have + Verb 3 + ...
- Positive: We should have left.
Negative: We should not have left so early. (Regret about past action). - Positive: He must have seen it.
Negative: He could not have seen it. (Logical deduction about the past). - Positive: They might have arrived.
Negative: They might not have arrived yet. (Past uncertainty).
Next, we will explore Negative Words & Double Negatives to learn how to negate sentences without using not, and why double negatives are grammatically incorrect in standard English.