Why is the verb for "pretexts ... and necessity ... was exposed" used in the singular in this quotation? [closed]

This is a very mangled version of the original (which is grammatical).

The original (found in Google books) is:

The pretext about the cold and the necessity for the cloak were thus exposed.

It seems difficult to believe that it is merely an independent translation of the French; the original is:

on comprenait dès lors la nécessité du rhume et l'urgence du manteau,

of which a relatively literal translation would be

at that point, he understood the need for the cold and the urgency of the cloak.

It is hard to imagine how an independent translation would have chanced to be so similar.