Breakdown of Ему нужно жильё на один месяц.
он
he / it (for a masculine noun) / it (for a neuter noun)
один
one
месяц
month
нужно
it is necessary
Questions & Answers about Ему нужно жильё на один месяц.
Why do we use на before один месяц to mean "for one month"?
This is the core rule for expressing intended duration. When you get, need, or borrow something with the intention of keeping it for a specific amount of time, you use на + the Accusative case. If you just said an amount of time without на, it would mean the action itself took that long to complete.
Why does the sentence start with Ему (to him) instead of Он (he)?
In Russian, the concept of "needing" something is expressed backwards compared to English. The person who needs something goes in the Dative case (here, Ему for "to him"). The thing that is needed is actually the subject of the sentence, so it goes in the Nominative case (жильё). Literally, the sentence says "To him, housing is necessary."
Why is the word for "needs" spelled нужно here instead of нужен or нужна?
The word нужно must agree with the gender and number of the thing being needed, because that thing is the grammatical subject. Since жильё (housing) is a neuter noun, we use the neuter form нужно. If he needed a masculine thing, like a ticket, it would be Ему нужен билет.
If на один месяц is in the Accusative case, why doesn't the ending of месяц change?