Learn French: Elles ont rencontré un ami avant-hier. - They met a friend the day before yesterday.

In French, the most common past tense is the passé composé (composed past). It is built using two parts: a helper verb (here, ont, which is avoir for elles) and a past participle. For regular verbs ending in -er like rencontrer (to meet), you drop the -er and add -é to get the past participle rencontré.

Since Elles is feminine plural, shouldn't rencontré have an extra "e" and "s" at the end?

No, and this is a great rule to remember! When the past tense uses the helper verb avoir (to have), the past participle (rencontré) normally does not change to match the subject. It stays exactly the same whether the subject is masculine, feminine, singular, or plural.

How does the word avant-hier work?

Avant-hier means "the day before yesterday." It is simply made up of two smaller words combined with a hyphen: avant (before) and hier (yesterday). Literally, it translates to "before-yesterday."

How do you pronounce Elles ont and un ami? Do the words run together?