The object, or when to use accusative, partitive, T-plural or basic form

Compare:
Mies maalaa taloa.
Mies maalaa talon.
Mies maalaa talot.

Mies maalaa taloa. Partitive, because right now, the man is painting the house. He's not finished yet, and for all we know he could stop any minute.

Mies maalasi talon. Genitive, because he painted the house, he finished it and did the whole house, not just a part of it.

Mies maalasi talot. Plural, because he painted a few houses completely, houses that have been mentioned before. A specific number of houses, not just some houses.


Compare:
Luen kirjaa.
Lue kirjan!
Luen kirjat.

Luen kirjaa. Partitive, because right now, I am reading the book. It's not finished, and I might never finished, but at least I'm busy doing it.

Lue kirja! Imperative. This is an order: read the book! Always basic form of the word.

Luen kirjat. Plural, because I read these books now and I will finishe them. They are a specific number of books, maybe some reading list the school gave me or something.



Compare:
Kirjoitan kirjeen äidille.
Minulla on aikaa kirjoittaa kirje nyt.

Kirjoitan kirjeen äidille. Genitive, because I write to my mom now, and I will finish it, I will reach my goal.

Minulla on aikaa kirjoittaa kirje nyt. Always basic form of the word with this kind of sentence construction. I have *something* *to do something* *to something*


Compare:
Juo maito kokonaan!
Hän juo koko maidon.

Juo maito kokonaan! Imperative. This is an order: drink all the milk! Always basic form of the word.

Hän juo koko maidon. Genitive, because he drinks all the milk. The whole glass, or the whole milk carton. He won't stop until it's gone.


Compare:
Minun pitää ostaa kynä.
Ostakaa minulle kynä, kun käytte kaupassa!

Minun pitää ostaa kynä. After "minun pitää", "minun täytyy" or "minun on pakko" you use the basic form of the word.

Ostakaa minulle kynä, kun käytte kaupassa! Imperative. This is a strong suggestion to someone: buy me a pen, when you go to the shop! Always basic form of the word.


Compare:
Katson varmasti säätiedotuksen.
Katson juuri säätiedotusta.

Katson varmasti säätiedotuksen. Genitive, because of the "varmasti". I will certainly watch the weather report. All of it!

Katson juuri säätiedotusta. Partitive, because I am doing it now. It's not finished yet, and I might never finish it.


Compare:
Poltatko sinä tupakkaa?
Polta tupakka nopeasti, meillä on kiire!
Unohditko tupakat?

Poltatko sinä tupakkaa? Partitive, because you can't count what they are talking about. It's just: do you smoke tobacco? Not for example: do you smoke all this tobacco?

Polta tupakka nopeasti, meillä on kiire! Imperative, so basic form of the word. Smoke your tobacco fast, because we're in a hurry!

Unohditko tupakat? Plural, because you want to know if the other person has forgotten all the tobacco. If he had forgotten just a part of it, there would be no use in asking. It's not genitive because you can't forget just one tobacco, it's not countable.


Compare:
Sinun on pakko tuoda kirja takaisin.
Tuo kirjat!
Tuo kirja!

Sinun on pakko tuoda kirja takaisin. After "sinun pitää", "sinun täytyy" or "sinun on pakko" you use the basic form of the word.

Tuo kirjat! It's imperative (which would normally just have the basic form of the word), but we are talking about a specific number of books here, all the books you need to return to the library for example. So: plural.

Tuo kirja! Imperative. This time we are talking about only one book, so we use the basic form of the word.


Compare:
On hauskaa rakentaa hiekkalinna.
En osaa rakentaa hiekkalinnaa.

On hauskaa rakentaa hiekkalinna. It's fun to build a sandcastle. With "on hauskaa" sentences you always use the basic form.

En osaa rakentaa hiekkalinnaa. I'm not able to build a sandcastle. This sentence is in the negative, so has to be partitive!


Compare:
Minulla on rahaa ostaa upea koru.
Minulla on rahaa. Ostan äidille upean korun.

Minulla on rahaa ostaa upea koru. Always basic form of the word with this kind of sentence construction. I have *something* *to do something* *to something*

Minulla on rahaa. Ostan äidille upean korun. Genitive, because I buy my mom one luxurious jewel. I will definately buy it, and I know I'll just buy one of them.


Compare:
Minä tunnen suomalaiset hyvin.
Minä tunnen suomalaisen hyvin.

Minä tunnen suomalaiset hyvin. I know all Finns well. Or a specific group of Finns.

Minä tunnen suomalaisen hyvin. I know one specific Finn well.


Compare:
Leena näkee kolarin.
Eilen hän näki kolme kolaria.
Hän muistaa kolarit.

Leena näkee kolarin. Genitive, because right now she is seeing a car accident. She is seeing the entire accident, and it's only one of them.

Eilen hän näki kolme kolaria. Poor Leena, yesterday she saw three car crashes... After numbers you always use the partitive.

Hän muistaa kolarit. She remembers the accidents. All four of them.


Compare:
Odota taksia!
Ota taksi!
En voi ottaa taksia, se on kallis.

Odota taksia! Imperative, which normally has the basic form of the word. Now it is partitive, because "odottaa" is a partitive verb, it gets always followed by the partitive.

Ota taksi! Imperative, take the taxi! Ottaa is not a partitive verb, so it is just the basic form of the word.

En voi ottaa taksia, se on kallis. Partitive, because the sentence is negative. I can't take a taxi, it's expensive.


Compare:
Minun täytyy hankkia tietokone.
Hankin tietokoneen.
Hankin tietokonetta.
Hanki minulle tietokone!
Kotiin hankittiin tietokone.

Minun täytyy hankkia tietokone. After "minun pitää", "minun täytyy" or "minun on pakko" you use the basic form of the word.

Hankin tietokoneen. Hankkia is a strange verb, with both the present and the past being "hankin". In this situation, the past tenseis used. I bought one tietokoneen.

Hankin tietokonetta. Partitive, because I buy a computer. I'm doing it right now, and I'm not yet finished.

Hanki minulle tietokone! Imperative. This is an order: buy me a computer! Always basic form of the word.

Kotiin hankittiin tietokone. This sentence is passive. "They" bought a computer the their home. Passive sentences always use the basic form of the word.