ils imposent

are necessary, are called for

→ imposer
impos to impose oneself, to intrude; to assert oneself + ent 3rd-person plural present ending
verb · 3rd-person plural, present tense Rare #49,233
are necessary, are called for In the expression « s’imposer », it means that something is necessary or appropriate.
FR: Des précautions s’imposent.
EN: Some precautions are necessary.
Conjugation of imposer
Indicative present
SingularPlural
First impose —
Second imposes —
Third impose imposent
Subjunctive present
SingularPlural
First impose —
Second imposes —
Third impose imposent

Des précautions s'imposent.

Precautions are in order.

— Star Trek IV : Retour sur Terre (1986)

Vu la nature de la population locale, des vêtements s'imposent.

Given the nature of the local population, certain types of clothing are necessary.

— Alien³ (1992)

J'ai pris des vêtements et les affaires personnelles qui s'imposent.

I packed the necessary clothes and personal items.

— Des hommes d'honneur (1992)

Des excuses s’imposent, peut-être.

An apology is perhaps in order.

— Zootopie 2 (2025)