她的对手脚踝受伤，不得不退出比赛。

Her ___opponent injured her ankle and had to withdraw from the match.

卡梅莉塔是她在排球决赛中的对手。

Carmelita was her ___opponent in the volleyball final.

这位拳击手仔细研究了他即将面对的对手的打法风格。

The boxer studied his upcoming ___opponent's fighting style carefully.