a redoubtable leader的用法和样例：
- He soon proved himself a redoubtable warrior, and won the respect of other soldiers.
- Our community is a leader in the conservation of wildlife.
- Old Liu might have pots of money and a redoubtable temper but he was no match for a penniless puffer who just managed to fill his stomach.
- The leader chastised that man who made a mistake.