Learn Dutch: We zullen vaak terugblikken op de momenten waarop we jong waren. - We will often look back on the moments when we were young.

Toen and als are conjunctions used to introduce a time clause (e.g., "When I was young, I played outside"). But here, "when" refers directly back to a specific noun (de momenten). In Dutch, you cannot use toen or als to say "the moments when". Instead, you use a relative pronoun structure meaning "the moments on which". Since you reflect on a moment (op een moment), we combine waar + op to form waarop.

Is terugblikken the only way to say "look back"?

You can also use the more literal terugkijken. However, terugblikken (from de blik, meaning "the gaze" or "glance") is an excellent B2-level verb. It is slightly more expressive and often used when reflecting nostalgically on abstract things like memories or history. Both verbs take the fixed preposition op.

Why is the verb waren pushed to the very end of the sentence?

The phrase waarop we jong waren is a relative clause adding extra information about de momenten. Relative clauses follow standard subclause word order, meaning all conjugated verbs get kicked to the end. Since waren is the only verb in that specific clause, it sits at the absolute end.

Since this lesson is about past habits, could we use instead of ?