Finnish Grammar - Cases - Partitive

Partitive - when to use it

Kadulla on tyttö. There is a girl on the street.
Kadulla ei ole tyttöä. There isn't a girl on the street.
Pöydällä on kynät ja paperi. The pens and a sheet of paper are on the table.
Pöydällä on kynät ja paperia. The pens and paper are on the table. (NB. The partitive is used with paperi because it is uncountable.)
Pöydällä on kyniä ja paperia. There are some pens and paper on the table.
Pöydällä ei ole kyniä eikä paperia. There aren't any pens or paper on the table. There are neither pens nor paper on the table. (NB. Ja cannot be used in this sentence, since it is a negative sentence! Use ~kä instead.)
Kynät ja paperi eivät ole pöydällä. The pens and paper aren't on the table.
Meillä on lapsi. We have a child.
Meillä ei ole lapsia. We don't have any children.
Meillä on lapsia. We have children. (NB. The nominative singular can't be used in this case!)

With all numbers greater than 1 and with 0 (use the singular partitive when it comes after the number and the plural when it isn't attached to it!):

Kadulla on kaksi poikaa. There are two boys in the street.
Huomenna minulla on viisi tenttiä. I have five tests tomorrow.
Sääennuste on luvannut nolla astetta huomiseksi. According to the weather forecast it will be 0 degrees tomorrow.
Meitä oli kolmesataa. There were three hundred of us.
Luentosalissa oli kolmesataa opiskelijaa. There were three hundred students in the lecture hall.
Lukijoita oli viisi. There was five people reading.
Kirjastossa oli viisi lukijaa. There were five people reading in the library.

With indefinite amounts of things, in particular, things that can't be measured very easily:

Huomenna ostan maitoa, leipää ja kananmunia. Tomorrow I'm going to buy milk, bread and eggs.
Lasissa on mehua. There is juice in the glass.
Tästä tulee riisipuuroa. This is going to be rice pudding.

Kirjoitan kirjettä sinulle. I'm writing you a letter.
Luen kirjaa, joka on hyvin mielenkiintoinen. I'm reading a book which is very interesting.

On mukavaa kantaa pientä sanakirjaa mukanasi. It's nice to carry a small pocket dictionary with you.
Olisiko mahdollista käydä Lapissa, kun on yötön yö? Would it be possible (for us) to visit Lappland when the sun is up twenty-four hours a day? Would it be possible (for us) to visit Lappland when they are having white nights?

NB. Some adjectives can be used in either the nominative or the partitive, but most Finnish teachers will tell you it is easier to just use them in the partitive (except for the following three, which are always in the nominative).

NB. If X is a noun, then it is always in the nominative, even if it is in a negative sentence!

Onpa ihme, ettei hän ole vieläkään kirjoittanut. How strange that he still hasn't written!
Ei olekaan ihme, ettei hän ole vieläkään kirjoittanut. It isn't really so strange that he still hasn't written.

Exceptions: The adjectives hyvä, paha and parempi are always in the nominative:

Olisiko parempi käydä kaupassa huomenna? Would it be better to go to the store tomorrow?
Onpa hyvä, että tulit! So good of you to come!
On hyvä, että välillä aurinko paistaa talvellakin. It's good that the sun shines once in a while even in wintertime.

Tänään navakkaa lounaistuulta, huomenna vaihtelevaa pilvisyyttä ja ukkoskuuroja. Today we'll have a strong southwester, for tomorrow possibly cloudy with thunderstorms.