I understand when we use Den instead of Der, but can I say: "Den apfel isst der mann?"
I had a bit of trouble with this, but once I did my research I was able to understand it and it is a simple rule to follow.
Der Mann isst den apfel is grammatically correct. However, what about
Den apfel isst der mann? Apfel is still the object being acted on, right? Does both sentences means exactly the same?
Der Mann isst den Apfel means -> the man eats the apple
Der Mann isst einen Apfel -> Apple is masculin than einen
Isst der Mann den Apfel? as a question means -> Does the man eat the apple?
Den (diesen) Apfel isst der Mann. -> Put the attention more on the apple
Have you read the Tips and Notes? You can find them by clicking on the light bulb in the lessons like here: https://www.duolingo.com/skill/de/Accusative-Case/tips-and-notes
I did, but it did not quite help me. It still doesn't make sense why is apple the object that is being acted upon in the sentence:
Bite, einen apfel. It is not eaten, it is simply being asked for.
I have used search and found some answers, it's not a perfect explanation but it looks like I will have to accept it anyway.
Maybe it makes sense to extend the sentence:
I'd like an apple, please -> Ich möchte bitte einen Apfel
Yes, after some more reading I realized Duolingo held a part of the sentence :)
Thank you for your time
They mean the same thing, emphasis is on the apple. Perhaps the speaker is answering a question, Was isst der Mann?
I read it as though the writer is italicizing the section that has moved forward. It's useful if you're writing poetry, and want certain words emphasized.
Yes, this is perfectly fine. In German the finite verb needs to have the second position in a normal sentence (questions, imperatives and subclauses work differently). While it would be the most standard choice to put the subject in the first position, it's not mandatory. The only important thing is that there is one and only one component of the sentence before the finite verb and all the other components after the verb take their standard positions.
If you added a temporal adverb (today), the standard sentence would be:
[Der Mann] [isst] [heute] [den Apfel].
But you can re-arrange the sentence to start with it:
[Heute] [isst] [der Mann] [den Apfel].
The second component has to be [isst].