perfect or adjective

[leftsidestory]

I am always confused by the use of perfect tense/ or sometimes an adjective in dutch, as it is not 100 percent clear to me.

For example, in the sentence:

Het restaurant was gesloten

Is it a pluperfect or is “gesloten” simply an adjective here?

[LeSNT2]

In this case it's the plusperfect or 'plusquamperfectum' (that's how I know it). I understand your confusion because 'gesloten' can also be an adjective. How do you know the difference?

Het restaurant was gesloten. = two verbs. If you only write 'het restaurant was' it doesn't mean anything.
Het gesloten restaurant was heel mooi. = one verb and 'gesloten' is an adjective. If you only write 'het restaurant was heel mooi' it does mean something.

That's the easiest way to understand the difference.