"A whole new laboratory will be expensive."
Translation:Et helt nytt laboratorium skal være dyrt.
Why is 'vil bli dyrt' and 'skal være dyrt' correct, but 'skal bli dyrt' marked wrong?
I don't know why Duolingo would accept "skal være dyrt". To my Norwegian ears "vil bli dyrt" is the natural choice.
"Et nytt laboratorium skal være dyrt" gives more a feeling of "is bound to be expensive" or "should be expensive"(ie the total investment should be high, if you really want a top quality lab). I am afraid my English isn't fluent enough to explain it better.
"Et nytt laboratorium vil være dyrt" is a sentence you may encounter in discussions leading up to possible investments in new equipment, before the actual contract is signed to purchase.