Breakdown of Ovo je igla kojom ću popraviti kaput.
biti
to be (sam, si, je)
ovaj
this (m) / ova (f), ovo (n)
kaput
coat
htjeti
to want (intent, will)
Questions & Answers about Ovo je igla kojom ću popraviti kaput.
Why do we use kojom here instead of koja?
Kojom is the instrumental case of the relative pronoun koji. It has to match the gender and number of the noun it refers back to, which is the feminine singular noun igla (needle). Because the needle is the tool being used to fix the coat, the pronoun must take the instrumental case.
Doesn't the phrase 'with which' mean we need the preposition s or sa before kojom?
Not in this case! In Croatian, when you do something using a tool or instrument (like a needle), you use the instrumental case all by itself. You only add the preposition s or sa to the instrumental case when talking about company, like doing an activity along with a person.
Why does the future tense helping verb ću come right after kojom?
The word ću is an enclitic, meaning it is a 'weak' word that naturally wants to take the second position in its clause. The relative pronoun kojom starts a brand new clause, so ću grabs the second slot immediately after it, before the main verb popraviti.
Is kaput in the nominative case here?
It looks like it, but it is actually in the accusative case because it is the direct object of the verb popraviti (the thing being fixed). For masculine inanimate nouns like kaput, the accusative form is exactly the same as the nominative form.