"They can reach us."
Translation:Ils peuvent nous atteindre.
By phone, we would say "elles peuvent nous joindre".
"Atteindre" is rather physical: "les flèches (arrows) peuvent nous atteindre" or figurative "ses paroles peuvent m'atteindre"
"nos" is a possessive adjective, masculine or feminine and plural: "nos amis sont ici" (our friends are here).
"nous" means "we" or "us" depending whether that personal pronoun is subject or object:
énous pouvons les atteindreé" (we can reach them) - "ils/elles peuvent nous atteindre" (they can reach us)
thank you. it's a bit confusing since i'm a native spanish speaker, so i rely heavily on it with french, which is useful but also can be detrimental.
for example some of the masculines in spanish (el carro) are different in french (la voiture)
in the case of nos, in spanish is used for both possesive, and sentences like this one: ellos nos pueden alcanzar.