"They are not yours."
Translation:Zij zijn niet van jou.
@weirdones: "niet" is used whenever there is no indefinite article, whereas "geen" is used when there is one. Some examples:
- "Zij zijn niet van jou." vs. "Zij zijn van jou."
- "Er is geen hond." vs. "Er is een hond."
- "Dat is niet de hond." vs. "Dat is de hond."
In the first and third examples, "niet" is used because there would be no indefinite article, but in the second example "geen" is used because there would be an indefinite article.
@lyds1177: That is a good way to look at it! However, "not" still can be used with "geen."
"Ik heb geen hond gezien." = "I have not seen a dog."
Hope this clears things up, guys!
EDIT: Looking back on what I wrote, I would like to clarify something. "geen" is used if there is no definite article if there is a noun. If there is no noun "niet" will always be used. So if there is a noun and there is no article at all, "geen" will be used.