a three-cornered contest的用法和样例：
- The election was a three cornered fight between Conservatives,Labour and SLD.
- It is a three ring circus to watch that silly dog play.
- He discarded a three,and picked up a Queen.
- Having three corners, horns, or projections.
- A three piece suite has two chairs and a sofa.
- For this shot, I need a three wood.