"My guitar is on the desk."
Translation:Моя гитара на столе.
стол here is in the prepositional case, which used here to indicate a location of the guitar:
my guitar - is where? - on the desk
case singular plural
nominative сто́л столы́
genitive стола́ столо́в
dative столу́ стола́м
accusative сто́л столы́
instrumental столо́м стола́ми
prepositional столе́ стола́х
my guitars - are where? - on the desks
мои гитары - на столах
I guessed it has to do with cases but in other courses a new case is presented before it’ s used
It would be great if Duolingo taught us the genders if nouns before they quizzed us on it
It is not foolproof, but you can usually tell the gender of a noun from its ending.
my answer: моя гитара стоит на столе. This is considered an error. Shows the correct answer: моя гитара лежит на столе. Why? Стоит or лежит? These are the two correct answers. Although there is another third correct answer: Моя гитара на столе.
Because eсть is implied. It is seldom used in Russian. If anything, you could say something like "гитара лежит на столе" (my apologies for possible misspelling)
Seldom in this context only, or seldom always? Considering I have seen a lot of 'у меня есть (...)' popping up.
It helped me to think of it in a different way:
Every form of 'to be' is omitted in Russian, I am a cat is Я кошка, without a 'am'. However, there is a one exception, that is used in a weird way sometimes. Есть means 'there is', in the sense of 'if im speaking very generally, there, somewhere is ...", so you can say things like "Бог есть" (there is a God ==> God exists) or "В доме есть собака" (there is a dog in the house).
(though if you want to say: The dog is there, at a specific place, you say "Там собака", literally "there".
Then, there is the weird Russian way of expressing possession, so instead of saying "I have a cat" they say "To me there is a cat" (У меня есть кошка). Thats just a standard expression of saying it. Apart from this one exception (which is used strangely sometimes) there is no word for 'to be' in russian.
There is water on the plate - В тарелке вода.
My guitar is on the desk- Моя гитара на столе.
Which one is used for 'on'? В or На? I thought В meant the word 'in'? Like in the taxi ( В такси)?
"There is water IN the plate (dish)" because a plate in this case is a kind of a container.