Breakdown of Водопроводная труба находится под раковиной.
находиться
to be located
под
under
раковина
the sink
водопроводная труба
the water pipe
Questions & Answers about Водопроводная труба находится под раковиной.
Why is под раковиной in the instrumental case?
Because под can take two different cases in Russian:
- Instrumental when it means location: under / beneath
- Accusative when it means motion toward a position under something: to under / underneath
In this sentence, the pipe is already located under the sink, so Russian uses the instrumental:
- под раковиной = under the sink
Compare:
- Труба находится под раковиной. = The pipe is under the sink.
- Положи трубу под раковину. = Put the pipe under the sink.
So:
- под раковиной = location
- под раковину = movement/direction
Why does раковина become раковиной?
Because раковина is a feminine noun, and after под in the meaning of location, it must be in the instrumental singular.
The forms are:
- nominative: раковина
- instrumental: раковиной
This is a very common feminine singular instrumental ending:
- -а → -ой / -ей
- раковина → раковиной
- лампа → лампой
- дверь → дверью (different pattern, because it is a different noun type)
So раковиной is simply the grammatically required form after под here.
Why is it водопроводная труба and not just ?