a piece of porcelain的用法和样例：
- I need a piece of string to tie this parcel up.
- She was hit by a piece of falling masonry.
- I paid fifty pounds in the market for a so-called bargain piece of porcelain which turned out to be worthless; I'll just have to chalk it up to experience.
- The boy is daubing a piece of paper with red ink.
- Would you please give me a piece of paper?
- She tore off a piece of music and then went out.