"The purple dress is mine."
Translation:Den lila klänningen är min.
This is ridiculous. The more I go through the lessons the more guesswork the course feels like. We get questions before the questions chapter has even started. We have to guess half the answers because it's not covered anywhere in the lessons. It's getting extremely irritating. It's feels more like "guess till you find the right answer by dumb luck" than any actual learning...
Thanks a lot! I don't remember "de" ever being covered in a lesson. I definitely knew about "det" and "den", though.
Aren't "det" and "den" also used depending on whether or not an idea or object has been previously introduced? For example: "Det är en stor hund. Den är min hund." (referring to the dog that was introduced) But if only the sentence "Den är min hund" was said, then it would be incorrect because a "hund" has not been introduced, right?
So, which one prevails? Choosing "det/den" based on gender or choosing "det/den" based on whether or not it has previously been introduced? Is it preference or rule?
Would this example be incorrectly translated as "Det lila klänningen är min" as opposed to "Den lila klänningen är min."?
What about a standalone sentence such as "Den bord är vitt"?
The most important thing is to always use det with things that have not been previously introduced in a construction like "det är X'.
In my first example, Det är en stor hund. Det är min hund, you can see that the dog has in fact been introduced in the first sentence, but it's still best to refer to it with det in the second sentence. This is because det is still not really referring to the dog, but to 'the thing I am talking about'.
For your examples:
With definite noun + adjective, you always have the article, and the article of course has the same gender as the noun.
So "Det lila klänningen är min" is wrong.
Article + definite noun with no adjective means 'that …'
So det bordet means 'that table'.
Again, the article always has the same gender as the noun, there are no exceptions from this.
Det bordet är vitt 'That table is white'
Den boken är vit 'That book is white'.
In the introductory construction, Det är en hund, det is not an article (it is a pronoun) and does not refer to the dog, so it's always det.
On the other hand, if you're really referring to the dog with a pronoun, that pronoun is used to replace the word 'dog', so the word 'dog' isn't in the sentence. Den är min. 'It is mine'.
So the choice between Det är en stor hund. Det är min hund or Det är en stor hund. Den är min. is just a question of preference (mainly based on how closely tied together the sentences are I think), but there are a lot of other rules at play that are really rules.
More about 'det är' here: https://www.duolingo.com/comment/9708920