Breakdown of Als hij blij is, werkt hij fluitend.
zijn
to be
hij
he / it (referring to a 'de'-word)
blij
happy
werken
to work
Questions & Answers about Als hij blij is, werkt hij fluitend.
How do we form fluitend (whistling) in this sentence?
Fluitend is the present participle of the verb fluiten (to whistle). You form it simply by adding a -d to the full infinitive. In this sentence, it acts as an adverb to describe exactly how he works.
Why does the second part say werkt hij instead of hij werkt?
Because the sentence starts with a subordinate clause (Als hij blij is). In Dutch, if a sentence starts with anything other than the main subject, the main clause that follows must use inversion. This means the verb (werkt) swaps places with the subject (hij).
Why is the verb is placed at the very end of Als hij blij is?
Because the word als (when/if) introduces a subordinate clause. A major rule in Dutch grammar is that in subordinate clauses, the conjugated verb gets pushed to the very end of that clause.
Does als mean "when" or "if" here?
It can mean both! Als is used for both "if" (a condition) and "when" (for recurring events in the present or future). The translation provided uses "when", but "If he is happy..." would also be a perfectly correct way to understand it.