Do you think هُناك is needed in this sentence, since there is already في بَيْتي? It seems redundant, because both indicate the place whe Something is (or is not). Well, at least I wrote لَيْسَ كِتاب قَصير في بَيْتي and it was rejected.
Removing هناك would require re-arranging the sentence a bit, and abandon the use of ليس.
If I was in Duolingo's shoes I would put the sentence more like: لا يوجد كتاب قصير في بيتي (there is no short book in my house) - whatever "short book" means.
ليس في بيتي كتاب قصير
That's an acceptable alternative. Sounds a bit stilted for everyday use, but then again, all of MSA is.
what does يوجد means ?
It literally means "is found".
Is not found -------> ( لا یوجد) .
If you change the sentence like that Would that be also used in Arabic in such form? Cuz my Egyptian friend also suggested i use the same form and I want to use whatever that sounds more natural...!
The sentence starting with لا يوجد?
Yep, that's definitely acceptable in MSA (and I might as well say we are used to this form more than the one used by Duolingo, from cartoons dubbed in Arabic).
Thank you again, angel! Okay then im gonna memorize this one also....hehe
best of luck :)