"The cat is sleeping." is not possible?
"đi" means "go." I would translate it to "the cat is going to sleep."
I tried "the cat is going to sleep.", it says that my answer is incorrect.
Perhaps because the course use the progressive sentences with the marker đang before the verb. Just try reporting to add the sentence. ;)
why is 'a cat' incorrect here?
Using this sentence in real life, it sounds like you would talk about a specific cat. In English, 'The cat' is more specific than 'a cat'.
Is this "go to sleep" as in "goes somewhere to sleep" or in the same sense as to fall asleep?