Learn Hardcore Russian: Мой друг знает секрет.

In Russian possessive pronouns agree in gender, number, and case with the noun they modify. Друг is a masculine noun in the nominative singular, so you use Мой (masculine nominative), not Моя (feminine) or Моё (neuter).

What gender and case is друг, and how do you know?

Друг (“friend”) is masculine and here it’s the subject of the sentence, so it’s in the nominative case. Nouns in the nominative case usually answer the question “who?” or “what?”—in this case, “Who knows the secret? My friend.”

What case is секрет in and why does its ending not change?

Секрет is the direct object, so it takes the accusative case. Because секрет is an inanimate masculine noun, its accusative form is identical to the nominative. That’s why you still see секрет rather than a different ending.

What does the ending -ет in знает indicate?

The verb знать (to know) in the present tense is conjugated as: я знаю, ты знаешь, он/она/оно знает, мы знаем, вы знаете, они знают. The ending -ет marks the 3rd person singular (“he/she/it knows”).

Where is the stress in знает and секрет, and how do you pronounce them?