Question

Nous avons acheté un appartement .............. nous allons renouveler.

Hint:

Use “que” when the noun you're referring to is the direct object of the following clause.

Answer 1

Here, “un appartement” is the direct object of “renouveler.”
We need a relative pronoun that replaces a direct object → use “que.”
Since the verb already has a subject “nous,” “que” works perfectly.
Correct sentence: Nous avons achet´e un appartement que nous allons renouveler.