Translation:The constructions were very expensive.
I agree. I would be more apt to say construction projects which would be shortened to projects. I'm sure it's an actual word but I can imagine getting some strange looks if I said constructions in a conversation. However I suppose the purpose of this is to learn the Danish word for more than one construction project.
Construction could mean structure if talking about a finished building I suppose. That was just the way I interpreted the sentence. Also, I still wouldn't use the plural form in English to mean the different aspects of one building. I was just wondering if that was the best way to portray the meaning in Danish.
Although that was true in past centuries in literature, however in modern speech dear means loved/close to the heart, and expensive means something that costs a lot of money. Dear and expensive are in no longer interchangeable in modern English. This I say as a native speaker. Considering what they charged me in the hospital when my kids were born, I can see the confusion:)