нам следовало

we should have

→ мы
phrase Rare #48,176
we should have Used with an infinitive to express that it would have been better or more appropriate for us to do something. Нам literally means “to us,” and следовало is an impersonal past-tense form.
RU: Нам следовало проверить документы заранее.
EN: We should have checked the documents in advance.

Нам следовало быть осторожными.

We should have been careful.

— Двойная страховка (1944)