Learn Italian: Il nostro spazio comune è sempre pulito.

In Italian, you almost always need a definite article (like il, la, i, or le) before a possessive word. While English just says "our space", Italian requires "the our space" (il nostro spazio). The main exception to this rule is when talking about singular family members.

The lesson is about independent possessive pronouns (like "ours"). How would we change this sentence to say "Ours is always clean"?

You would simply drop the noun and say Il nostro è sempre pulito. In Italian, possessive pronouns (like "ours") look exactly the same as possessive adjectives (like "our"). You keep the article il because it stands in for the masculine singular noun spazio that was removed.

Why doesn't the adjective comune end in -o to match the masculine noun spazio?

Comune belongs to a group of Italian adjectives that naturally end in -e. These adjectives don't change to match gender, so they use the exact same -e ending for both masculine and feminine singular nouns. If we were talking about plural spaces (gli spazi), it would change to comuni.

Why does sempre go between the verb and the adjective?