Questions & Answers about Die Erbstücke, die wir zeigen, sind sehr wertvoll.
Why is the second die in the accusative case?
The second die is a relative pronoun meaning "that" or "which". It refers back to the plural noun Die Erbstücke. Inside its own mini-sentence (die wir zeigen), wir is the subject doing the action, and the heirlooms are the direct object being shown. For plural nouns, the accusative relative pronoun is exactly the same as the nominative: die.
Why is the verb zeigen at the very end of the middle phrase?
The phrase die wir zeigen is a relative clause, which is a type of subordinate clause. In German, there is a strict rule that the conjugated verb must be pushed to the very end of any subordinate or relative clause.
Why does the verb sind come right after zeigen?
The verb sind belongs to the main sentence, matching the subject Die Erbstücke. If you temporarily ignore the extra information in the middle, the core sentence is simply Die Erbstücke sind sehr wertvoll. The second comma tells you that the relative clause is over and the main sentence is resuming.
Are the commas around die wir zeigen strictly necessary?
Yes! Unlike in English, where you can sometimes drop commas around "that" clauses, German requires you to fence in your relative clauses with commas. You need the first comma to show where the extra information begins, and the second comma to show where the main sentence picks back up.