"Je suis seule dans la cuisine, un chat sur les genoux."
Technically, either les or mes is correct in this sentence.
Mes is seldom used in regular conversation when referring to body parts. To prove the point that both are legal, there is another Duo exercise where mes is used in almost the exact same situation.
The above is based on Sitesurf, about.com and other comments
My guess is that using possessive mes with body parts is seen as getting a little too personal in conversation.
http://french.about.com/od/vocabulary/a/parts-of-the-body.htm "the possessive adjective is almost never used with body parts in French."
I'm not sure about the rule (or whether there is one), but I've noticed it in other instances. I don't think "mes" is necessarily wrong, but they do use "les" in such cases.
French always uses a definite article and not a possessive with body parts! Just how it works.
Where I grew up, everyone would say "in my lap" rather than "on my lap", especially for small cuddlies like kittens and children. "On my lap" had a sense of unwelcomeness, as in "I spilled a cup of coffee on my lap". Perhaps this should be considered as an alternate? What do you think?
What the heck is this sentence supposed to mean, anyway? I tried to find it in french idioms and couldn't.
Just what it says. It could be the intro to a story, for example, "I'm alone in the kitchen with a cat on my knees, reading a book, when suddenly the doorbell rings."
Yes, thank you bronso. I figured it out after a little while. I was thinking the same as pastafarianist, above. This is the reason it didn't make sense to me. It makes perfect sense "I am alone in the kitchen with a cat in my lap."