* Cloth (without an article) is a general term referring to any woven or knitted material. It's like a category or type of material:
* "The dress is made of silk cloth."
* "He bought some cotton cloth to make a shirt."
* A cloth (with an article) refers to a specific piece of cloth, usually with a defined purpose:
* "She wiped her tears with a cloth."
* "He used a cloth to clean the table."
* "The painter brought a drop cloth to protect the floor."
Think of it this way:
* Cloth: the *material* itself
* A cloth: a *specific item* made from that material
Let me know if you have any other grammar questions!