Breakdown of Das Kühlsystem hat komplett neu reguliert werden müssen.
haben
to have
neu
new
müssen
to have to, must
werden
to be (passive auxiliary + past participle)
Questions & Answers about Das Kühlsystem hat komplett neu reguliert werden müssen.
Why is the sentence using the infinitive müssen instead of the past participle gemusst?
This is due to the "double infinitive" rule. When a modal verb is used in the Perfekt tense alongside another verb, it drops its normal past participle (gemusst) and takes its infinitive form (müssen) instead. Because it sits next to the passive auxiliary werden, you end up with two infinitives in a row at the end of the sentence.
Why does this passive sentence use hat instead of ist?
Standard passive sentences in the Perfekt tense use a form of sein (e.g., Das System ist reguliert worden). However, because we added the modal verb müssen, the helping verb changes to haben. All modal verbs require haben to form the Perfekt tense, even when they are part of a passive construction.
What is the rule for the word order of the three verbs at the end: reguliert werden müssen?
In a main clause like this, the verb cluster goes at the very end in a strict order: the main verb's past participle (reguliert) comes first, then the passive auxiliary (werden), and finally the modal infinitive (müssen). The modal verb anchors the absolute end of the sentence.
How does neu reguliert translate to "readjusted"?