Meaning: The footwear had small pieces of rock or minerals completely occupying it.
Choice of Words: Shoes: coverings for the feet. Filled: completely occupied or covered. Sand: small, loose particles of rock or mineral.
Alternative Expressions
Shoes containing sand.
Meaning: This sentence also describes shoes that have sand inside them, but it does not specify whether the shoes are completely full of sand or not.
Choice of Words: The word "containing" means to hold something inside. It is similar to the word "filled" but it can also be used to describe something that is not completely full. In this case, we are talking about shoes that have sand inside them, but it is not necessarily full of sand.
Sand-filled shoes.
Meaning: This sentence is the most concise way of describing shoes that have sand inside them.
Choice of Words: The word "sand-filled" is a compound word that means "filled with sand". It is a more concise way of saying "shoes filled with sand" or "shoes containing sand".