a three-legged stool的用法和样例：
- And the best I can say is describing Intel as a three legged stool,the three legs are design, technologymanufacturing,marketingsales.
- It is a three ring circus to watch that silly dog play.
- He discarded a three,and picked up a Queen.
- Operators of explosives reactors had to sit on a one legged stool to ensure that they stay awake!
- A three piece suite has two chairs and a sofa.
- "among the finds are zun (jars), Ding (cauldrons), which is a three legged or four-legged cauldron for holding meat and cereal crop;"