Learn Dutch: We hebben gisteren iets authentieks moeten taxeren. - We had to appraise something authentic yesterday.

When an adjective comes directly after an indefinite pronoun like iets (something), niets (nothing), veel (much), or wat (some), you must add an -s to the end of it. This is known as the partitive -s. Therefore, the translation for something authentic becomes iets authentieks.

Why are there two infinitives (moeten taxeren) instead of a past participle like gemoeten?

This sentence uses the double infinitive rule. In the present perfect tense, when a modal verb like moeten is combined with another verb (taxeren), the modal verb does not get a past participle. Instead, it stays in its infinitive form. That is why we say hebben moeten taxeren rather than hebben gemoeten taxeren.

Can I swap the order of the verbs at the end to say taxeren moeten?

No. In this specific double infinitive construction, the modal verb (moeten) must precede the main verb (taxeren).

Could the word gisteren be placed somewhere else in this sentence?

Yes, you could place gisteren at the very beginning of the sentence to place more emphasis on when the action happened. Just remember that doing so triggers word order inversion, making the verb come before the subject: Gisteren hebben we iets authentieks moeten taxeren.