самую

самую

"Самую" is the feminine accusative singular form of "самый," meaning "the most" or "the very."

The word 'самую' is used here as the feminine accusative singular form of 'самый,' meaning 'the most,' indicating that the adjective 'interesting' describes the noun 'book' with a superlative degree.

Я выбрал самую интересную книгу.

I chose the most interesting book.

In this sentence, 'самой' is the feminine dative singular form of 'самый,' used in correlation with the noun 'горе' indicating location.

Мы отправились к самой высокой горе.

We went to the highest mountain.

Here, 'самая' is the feminine nominative singular form of 'самый,' describing the superlative quality of the noun 'вещь.'

Это самая красивая вещь, которую я видел.

This is the most beautiful thing I have seen.