"Her work is very good."
Translation:عَمَلها جَيِّد جِدّاً.
I think you mean طيب
Well, جيد means good in general (as opposite to bad, or poor quality). طيب on the other hand is used in various way. Duolingo here uses it, to my knowledge, to mark the food as being delicious, which is OK but there are other words for delicious that are better used anyway. طيب also means "kind" (e.g. nice person).