ser Negative Imperative Conjugation
ser — to be
The negative imperative of ser uses 'no' + present subjunctive: no seas, no sea, no seamos, no seáis, no sean.
ser Negative Imperative Forms
When to Use the Negative Imperative
Use this to tell someone 'don't be' something, like 'don't be rude'.
Notes on ser in the Negative Imperative
Like all negative commands in Spanish, these are identical to the present subjunctive forms.
Example Sentences
No seas tonto.
Don't be silly.
tú
No sea tímido.
Don't be shy.
No seamos pesimistas.
Let's not be pessimistic.
nosotros
Common Mistakes
Mistake: Using 'no sé' as a command.
Correct: Use 'no seas' for 'don't be'.
Why: 'No sé' means 'I don't know'. Negative commands must use the subjunctive forms.
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Related Tenses
Present
yo: soy
The present of ser is highly irregular and essential: soy, eres, es, somos, sois, son.
Preterite
yo: fui
The preterite of ser shares the exact same forms as the verb 'ir' (to go): fui, fuiste, fue, fuimos, fuisteis, fueron.
Imperfect
yo: era
The imperfect of ser is one of only three irregular verbs in this tense: era, eras, era, éramos, erais, eran.
Future
yo: seré
The future of ser is regular: seré, serás, será, seremos, seréis, serán.
Conditional
yo: sería
The conditional of ser is regular: sería, serías, sería, seríamos, seríais, serían.
Present Subjunctive
yo: sea
The present subjunctive of ser is irregular: sea, seas, sea, seamos, seáis, sean.
Imperfect Subjunctive
yo: fuera
The imperfect subjunctive of ser uses the 'fuer-' stem: fuera, fueras, fuera, fuéramos, fuerais, fueran.
Affirmative Imperative
yo: sé
The affirmative imperative of ser is used for commands: sé, sea, seamos, sed, sean.