a piece of artillery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.
- As we have said, the great city resembles a piece of artillery;when it is loaded, it suffices for a spark to fall, and the shot is discharged.
- 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.