When is it that we don't use "ne" along with "pas" in a negative statement? [duplicate]

Question

The rule when you're negating a statement in French is, as I've been taught in A2/B1 French classes, a "ne" + word + "pas" syntax. However, I have seen that that doesn't apply in many sentences, like in the following:

J'y vais quelquefois, mais pas souvent

Why is it so in this case and in what instances do we drop the "ne" warning and negate directly with "pas"?

Answer 1

A "Ne + word + pas" is only valid when the word is a verb. There are exceptions though (B and C below) .

• Il ne sait pas encore bien parler. (verb)
• Les arcs en ciel ne sont pas visibles pendant bien longtemps après qu'ils ont commené à apparaitre. (verb)

B In the spoken language of everyday an enormous lot of people use the structure "verb + pas"; "ne" is not used. However, you can choose to use if it pleases you (not to forget : you might displease certain persons if you choose to use it). Remember also that in formal speaking you are considered a sloppy speaker if you do not use it. In a court of law, for instance, it is advised to use "ne" all the time during formal proceedings.

C Boutin-Grammaire (see this article for much more information on the negation)

Only "ne" is use in literary French in the following cases.

■ in certain proverbs and expressions
♦Qui ne dit mot consent.

■ when using the verbs "avoir", "savoir" and "pouvoir" followed by interrogative "que" and a verb in the infinitive.
♦ Il ne sait que dire. (Il ne sait pas quoi dire.)
♦ Je n’ai que faire de ses conseils. (Je n’ai rien à faire de vos conseils.)

■ when using the verbs "cesser", "pouvoir" and "savoir"
♦ Je ne saurais vous dire. (Je ne saurais pas vous dire.)

D If you need the negation for a noun, adjective or adverb (adverbial locution), then you do not use "ne". Those are however not called properly negative statements but negative locutions.

• Elle recherchait un beau jouet, mais pas un jeu éducatif. (noun group)

• Elle recherchait un beau jouet pas cher. (adjective)

• Il se remettait à l'ouvrage, pas de bonne volonté, mais avec la détermination de finir ce qui avait été commencé. (adverbial locution)

• La roue tournait sans cesse, pas rapidement, pas sans grincer ni sans de petits à-coups. (adverb)

E Statements that are ellipses, in particular in answers to questions or in statements that are meant as corrections.

• — Veux-tu de la purée ? (colloquial: Tu veux de la purée ?)
  — Pas sans beurre… (Je (ne) veux pas de purée sans beurre. or Je (n')en veux pas sans beurre)
• — Il est allé au cinéma !
  — Pas au cinéma, au théâtre !