Kennt die Studentin der Professor?
I don't understand why I can't use this? (In my mind it translates to "does the female student know the male professor")
"der Professor" should be "den Professor" (Accusative).
Nominative: the subject of the sentence: die Studentin
Accusative: the direct object of the sentence: der Professor, which becomes den Professor because of the declination
Jemand (die Studentin) kennt jemanden (den Professor)
Kennt die Studentin den Professor?
This is something which took me a while to get my head around but becomes second nature really fast.
This is all a question of cases within a sentence. I'll try my best to explain it.
I understand a case as a role within a sentence. So, for example, the nominative case has the role of doing/performing an action. This is the subject of the sentence.
The accusative's role is to show the object in the sentence, or in other words, the target of the action.
So an example: "The woman is eating the apple"
"The woman" = nominative, because she is performing/doing the action (eating) "the apple" = accusative, because it's being eaten (it's the target of the verb)
Because English doesn't show these cases like German does, by changing the article, it can be a bit of a headache at times.
So when you translate that example above into German, you get this:
"Die Frau isst den Apfel"
I deliberately used a food which is masculine in gender (der Apfel) to demonstrate how the masculine articles change in the accusative case.
No other genders will change in the accusative case. Here's a table to show the difference between the nominative (top) and accusative (bottom):
What I used to do when writing sentences is just take second to think about which noun in my sentence is taking which case.
Hopefully that's not too much of a ramble and helps a bit.
tl;dr version: "der" changes to "den" to express the accusative case, because "Professor" is the target of the verb "kennen".
(edited because the table didn't work)
Menino's and cash_moneyss's explanations are so great. I have nothing to add.
Just a thought: I'm just rewriting your words as follows: "Kennt der Professor die Studentin?" - Only a new word order. And that means: Does the (male) professor know the female student.
But in this case "die Studentin" is in the accusative. Here nominative and accusative are equal (for female nouns in the singular).
Sorry, I hope my English is understandable (it's certainly incorrect). I am a complete beginner (or rookie?) here. :-)
That is an interesting point. The following sentences, while similar, have different meanings:
- Die Studentin (nominative) kennt den Professor (accusative). - The (female) student knows the (male) professor.
- Die Studentin (accusative) kennt der Professor (nominative). - The (male) professor knows the (female) student.
The word order in the second sentence has an emphasis on "die Studentin" and could be an answer to "Wen kennt der Professor? (whom does the professor know?)". The word order in the first sentence is more common.
It can be both depending on the situation:
If "die Studentin" is one female student among other female students and you want to know which one the professor knows the emphasis would be on "die".
If "die Studentin" is the only female student among other persons the emphasis would be on "die Studentin".
Agreed. - But we should say to those who learn German here: It's possible to speak like this. But it is more a theoretical matter.
I could only imagine it this way: "Die Studentin? Die kennt der Professor (schon)." ["The student? The professor (already) knows her."]
But I'll stop. - What will Meg think of us?!