Questions & Answers about Nu besef ik dat zij de fout eerder hadden ontdekt.
Why does the sentence say besef ik instead of ik besef?
Because the sentence starts with the time word Nu (Now). In Dutch, the main verb must always be in the second position. When you put a word like Nu at the front, the subject (ik) has to swap places with the verb (besef) to keep the verb in the second spot. This is called inversion.
The word zij can mean "she" or "they". How do we know it means "they" in this sentence?
You can tell by looking at the helping verb that goes with it. The auxiliary verb here is hadden (had), which is plural. If the sentence were about "she", it would use the singular form had: ...dat zij de fout eerder had ontdekt.
Why are the verbs hadden and ontdekt placed at the very end of the sentence?
The word dat (that) introduces a subordinate clause. In Dutch subordinate clauses, all the verbs are pushed to the end. So the past perfect combination hadden ontdekt (had discovered) moves to the end of the phrase.
Does the helping verb hadden have to come before the past participle ontdekt?
No, in a subordinate clause you have a choice! You can put the helping verb either before or after the past participle. Both ...hadden ontdekt and ...ontdekt hadden are perfectly correct and sound natural to native speakers.