a vicious rumor的用法和样例：
- He gave the dog a vicious blow with his stick.
- Later on she stopped leading a vicious life.
- Be careful, the mule is a vicious beast, not safe abaft the beam.
- The editor got his claws into the opposition in a vicious editorial.
- The people are held down by a vicious and repressive military regime.
- He fought a vicious smear campaign against them.