Answer:
"De" is a very common preposition in French and can have many different meanings and uses. Here are some of the most common uses of "de" in French sentences:
To show possession or ownership: "le livre de Pierre" (Pierre's book)
To indicate the material of which something is made: "une table en bois" (a wooden table)
To indicate a part of something: "un morceau de gâteau" (a piece of cake)
To indicate quantity: "une bouteille de vin" (a bottle of wine)
To indicate origin or source: "un cadeau de mes parents" (a gift from my parents)
To indicate purpose or function: "une chaise de bureau" (an office chair)
To indicate a comparison: "plus grand que" (bigger than)
To indicate a relationship between two nouns: "un ami de Pierre" (a friend of Pierre's)
To indicate a time period: "un film de deux heures" (a two-hour movie)
These are just a few examples of the many uses of "de" in French sentences. In general, "de" can be used to indicate possession, material, quantity, origin, purpose, comparison, relationship, time period, and more.