"You do not have a skirt, Carrie."
Translation:لَيْسَ عِنْدِك تَنّورة يا كَري.
Laysa (ليس) is used with nominal sentences (or semi-sentences) mostly to negate the existence or negate the status of something. It is almost equal to the English Not in some sense. It might come before some verbs BUT with some specific arrangements. In Arabic grammar books and under the Arabic grammar scheme, ليس is considered a verb itself, and it has a feminine counterpart: ليستْ (Laysat).
Lá (لا) is used before verbs, specifically in imperative (for negative imperative mode) or present. It is a particle for negating (and also translated simply to No for answering). It can come before nouns at times but such usage is rather "poetic" in nature or maybe in some fixed expressions.
Example: I don't understand can be rendered with both, Laysa and Lá:
- لَسْتُ أَفْهَمْ (lastu afham): Here, the central (Y) was removed and the (tu) at the end stands for (me), so (lastu) means something like (I do not). (afham) is (I understand). Together, the stand for I do not understand or if I want to be a bit more precise it would sound something like I am not understanding.
- لا أَفْهَمْ (lá afham): This one is rather straight forward. (afham) is (I understand) and we just place (lá) before it to make it as (I do not understand).
I used here a verb just to show the type of re-arrangement that would occur when we use ليس to negate. Anyway, it's not always required. Generally speaking, ليس is introduced to a nominal sentence to negate it; Something like I have not for example or something like This is not… (something). Just few examples.
Hope that sheds some light.
Most welcome. Don't worry if you don't understand it now. My guess it might come to you naturally later on providing the right exposure. Unfortunately, Duolingo is a bad place to go deeper into Arabic; The benefits of this course won't go beyond knowing few words and the letters. The bulk must be done outside. Needless to say, Duolingo's course is a mix of standard and dialects (some Egyptian and some Lebanese and probably others). And just to note, Laysa is not used in dialects.
As I've mentioned, Laysa is considered a verb in Arabic grammar scheme. It's a bit hard to explain under the umbrella of Western grammatical scheme. The terminology and the divisions of the parts of speech in Arabic are quite different and often books teaching the subject would try to "bend" or "twist" some information to approximate some ideas to the readers, specifically those who are used to the Western scheme of grammar and its divisions of speech (i.e. cases, tenses, etc).
I think at this point in Duolingo, it would be just enough to remember that عند (3ind) means at and also used for to have - and to negate that, Laysa is used before that preposition.