"고래는 넥타이를 매요."
Translation:The whale puts on a tie.
In American English, “whale” can be a derogatory term for obese people. It is probably not the case in Korean though, so the translation would not make sense.
Part of Duolingo is to put ib random nouns into sentences so you learn them. The sentence technically makes sense and that's what matters.
Same. Unless you get to sentences like "He hates himself." or "I have very long banana." and you be like "Eh. Maybe not the best children's book.", but a hella funny one.
By the way to be completely honest, the sometimes very weird and off-putting sentences actually help a lot for remembering the words used in these, because they are so weird.
In English and using the animal form of whale, this sentence still makes sense. It is something that is unlikely to occur in nature, but the sentence makes sense. Imagine you're watching an animated movie, sort of like Finding Nemo, you could easily say such a sentence and it would make perfect sense in that scenario. Also, as Jasmine said, these random sentences are to help you learn various types of vocab. The aim isn't to memorise the exact sentence, but to learn the sentence form and to be able to substitute in your own words.