Breakdown of Это большой успех, к которому мы давно идём.
это
this / it is
мы
we
большой
big
идти
to go (on foot) / to proceed, go (of a process)
Questions & Answers about Это большой успех, к которому мы давно идём.
Why is it к которому in this sentence?
Которому is the dative case of который (which). We use the dative here because of the preposition к (to/toward). The word is masculine to match the noun it refers back to, успех (success).
Why is the preposition к right in the middle of the sentence instead of at the end?
In English, we often leave prepositions at the end of a sentence (like the "toward" in "moving toward"). In Russian, prepositions are never left dangling at the end. They must come immediately before the word they are attached to, which in this case is которому.
The English translation says "we've been moving", but isn't идём present tense?
Yes, идём is the present tense of идти (to go). In Russian, when an action started in the past and is still happening right now, you use the present tense. This often happens with the word давно (for a long time).
Why use идём (we are walking) for an abstract concept like success?
Just like in English, verbs of motion in Russian are often used metaphorically. Идти к literally means "to walk toward", but in this context it means working or making continuous progress toward a goal.