a mortal combat的用法和样例：
- They fiercely disputed which of them should drink first, and were soon engaged in the agonies of a mortal combat.
- a fatal accident; a deadly enemy; mortal combat; a mortal illness
- There was not a mortal man in the park.
- You have come to challenge me in mortal combat.
- A demigod is the offspring of a god and a mortal.