Learn French: Ce projet ouvre de vastes horizons. - This project opens vast horizons.

This is the main rule for this lesson! Normally, the plural indefinite article for 'some' is des. However, when a plural adjective comes before the noun in French, des changes to de. Since the adjective vastes is placed before the noun horizons, we use de.

Wait, ouvrir is an -ir verb. Why does it end in -e here (ouvre) instead of -it?

The verb ouvrir (to open) is a bit of a trickster. Even though its infinitive ends in -ir, it is conjugated exactly like a regular -er verb in the present tense. That is why it takes the regular -er ending -e for the third-person singular (il/elle/ce projet ouvre). Other verbs that do this include offrir (to offer) and découvrir (to discover).

I learned that adjectives usually go after the noun. Why is vastes before horizons?

You are right that most adjectives follow the noun. However, a specific group of common adjectives always goes before it. You might remember the acronym BANGS (Beauty, Age, Number, Goodness, Size) from earlier lessons. The adjective vaste (vast, large) fits into the Size category, so it naturally precedes the noun.

Do we make a liaison between and ?