What are the differences between какой and что?
I know that when used in interrogation, какой can mean either "what" or "which", but, when both of them mean "what", what are the differences between them??
In russian - it's not big different, it's a two different words, even not synonymous.
Какой - it's the question of quality properties. Какой сегодня день? - What day is today? Какая сегодня погода? - What is the weather today?
Что - it's interrogative or union word is used in the formulation of the general question of the object, phenomenon, action in matters of inanimate subjects. Что случилось? - What happened? Я знаю, что он уже был там. - I know that he was there. Мы видим, что за этим кроется. - We see what lies behind it. Что сто́ит? - How much is?