"Sehen Sie den Lehrer?"

Translation: Do you see the teacher?

[linmn]

Why is "Do they see the teacher?" wrong?

[Ilchymis]

I am wondering the same. Would it not be something like "Siehst Sie den Lehrer"?

[casper911ca]

I wrote. "Did you see the teacher?" Which is wrong. I'm guessing because its present tense and not past tense...
Also a little fuzzy on the used of "den". Why not "der?"

[Hohenems]

You're right about the present tense. "Den" instead of "der" because it is a masculine (singular) noun, and it is in the accusative case.
Case link: http://coerll.utexas.edu/gg/gr/cas_01.html
Definite article link: http://en.wikipedia.org/wiki/German_declension#Definite_articles.5B1.5D

If this seems overwhelming, my suggestion is to bookmark the pages and refer to them often. With just a little practice (and studying) you'll get the general gist of it and be able to answer some of your own questions. And if not, then just keep asking!

[casper911ca]

I see! Thank you.

So for two masculine nouns, one the subject, the other the object:

der [subject] VERB den [object].

"der" marks the subject, and den marks the object, so it would follow that the following would have the same meaning (regardless of order of the subject and object, unlike English where order matters):

den [object] VERB der [subject].

[Kukuburra]

The hover-over offers Lehrer as teacher or teachers. How does this one work?
Is it like "gemüse?" Such as taking the plural form always and marking it with das or die?

[Armelle47]

How can I tell if SIE refers to YOU, and not THEY? "Do they see the teacher" was marked wrong.