I have a question:
- "A paper", is this usage correct?
- Or should I say "a sheet of paper"?
I have a question:
We typically count physical units of paper in pieces or sheets:
Could you hand me a sheet of paper?
Could you hand me a piece of paper?
We typically use sheet when the paper is a regular size. For example, we would use sheet if you had twenty pieces of paper, all the same shape and size, which you could easily place in a stack.
Piece is more general, and can refer to any size or shape. If you tear off the corner of a sheet of paper, you have a piece of paper.
We don't typically count physical paper without one of these words. However, the word paper has various other meanings. For example, if the word refers to a newspaper, we don't say sheet or piece:
I saw an article about losing weight in the paper.
The same is true if the word refers to an academic paper:
Have you read Shigeto Kawahara's new paper about geminate devoicing in Japanese?
But most people wouldn't normally refer to a sheet of paper as "a paper".