- "Что вы думаете о вашей лошади?"
- "Что ты думаешь о твоей лошади?"
When you use the word "about" (generally: "о" when followed by a consonant, "об" when followed by a vowel or "обо" when followed by the word "мне"), the consequent phrase (the thing that the "about" is about) has to be in the locative/prepositional case -- the same one that you use with "в" to indicate "located at"...
- the locative of the (feminine) noun "лошадь" is "лошади",
- the feminine singular locative of "ваша" is "вашей",
- the feminine singular locative of "твоя" is "твоей".
Hence as above.
(P.S.: this is an area where I'm shakier, but I think you can also use "свой" in this case, so for example:
- "Что вы думаете о своей лошади?"
- "Что ты думаешь о своей лошади?"
But I'm certainly willing to be corrected on this last.)
"kak" means how or as. "что" means that, what, which.
First off, thank you for not attacking the course about learning weird sentences. I have encountered those types of people, and they are unpleasant. I also agree that this sentence is weird, but it is useful. If you were to translate it literally, it would be "what think your horse". This seems awkward to an English speaker, but to a Russian speaker this is natural, since that is the way sentences are formed. While i agree that we probably would never use this sentence, it teaches us how to use Russian grammar.