Breakdown of Это самый лучший учитель, но он нас то хвалит, то ругает.
это
this / it is
он
he / it (for a masculine noun) / it (for a neuter noun)
учитель
teacher
нас
us
Questions & Answers about Это самый лучший учитель, но он нас то хвалит, то ругает.
How does то ..., то ... work in this sentence?
The paired conjunction то ..., то ... is used to show alternating actions or states. Here, it connects the two verbs хвалит (praises) and ругает (scolds) to show that the teacher switches back and forth between these two actions.
Why do we say самый лучший? Doesn't лучший already mean best?
You are right that лучший means best or better, but in Russian it is very common to add самый to it for emphasis. Even though it literally translates to the most best, самый лучший is the standard way to say the absolute best in everyday Russian.
Why are хвалит and ругает in the imperfective aspect?
We use the imperfective aspect here because the actions are repeated and ongoing. The structure то ..., то ... describes a recurring cycle of events, so the verbs connected by it almost always need to be imperfective.
Why is the pronoun нас placed before the verbs?
In Russian, object pronouns like нас often move before the verb. Placing it before the то ..., то ... structure applies the word us to both verbs at once, keeping the focus on the contrast between praising and scolding without needing to repeat the pronoun.