Breakdown of Os reis não foram derrotados pelo exército.
ser
to be
não
not / no
por
through / by / for / because of
o rei
the king
Questions & Answers about Os reis não foram derrotados pelo exército.
Doesn't foram also mean "they went"? How do I know it means "they were" here?
You are right! The verbs ser (to be) and ir (to go) share the exact same forms in the simple past tense. You can tell it means "they were" here because it is followed by a past participle (derrotados) to form the passive voice. The context makes it clear that "they went defeated" is not the intended meaning.
Why does derrotados end in an 's' here?
In the passive voice, the past participle (derrotados) acts like an adjective. It must agree in gender and number with the subject receiving the action. Since the subject is Os reis (masculine, plural), the past participle must be masculine and plural as well.
Why do we use pelo instead of just por for "by"?
The passive voice uses the preposition por to introduce the agent (whoever is actually doing the action). Because "the army" requires the definite article o (o exército), the preposition por merges with o to create the contraction pelo (by the).
Where does the negative word não go when there is a two-part verb phrase like foram derrotados?
In Portuguese, não always goes immediately before the conjugated verb. Even though the passive voice uses a multiple-word verb phrase, the não never splits the verbs; it stays right in front of the helping verb (foram).