a piece of card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.
- 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.
- Stencils - draw outlines of a circle, square, rectangle and triangle on a piece of card and cut them out.