Breakdown of Я знаю девушку, которой ты уделяешь внимание.
я
I
ты
you (singular)
знать
to know
девушка
young woman
Questions & Answers about Я знаю девушку, которой ты уделяешь внимание.
Why is которой in the Dative case?
In Russian, the phrase уделять внимание (to pay attention) requires the Dative case for the person receiving the attention. So, которой is Dative because it acts as the receiver of your attention in the second half of the sentence.
How does которой know to be feminine singular?
The word который (which/who) always matches the gender and number of the noun it refers back to in the first half of the sentence. Since it refers to девушку (feminine, singular), it must also be feminine and singular.
In English we say "the girl you pay attention to", skipping the word "who" or "that". Can we skip которой in Russian?
No, Russian grammar doesn't allow you to drop the connecting word. You must always include the correct form of который to link the two parts of the sentence.
What does the verb уделяешь actually mean on its own?
Уделять (here in the "you" form, уделяешь) means "to allot", "to spare", or "to give a portion of something". The fixed phrase уделять внимание literally means "to allocate attention".
Just to review, why is it девушку instead of девушка?