看到那只龇牙的狗，邮递员小心翼翼地后退了。

Seeing the snarling dog, the postman cautiously ___backed ___off.

尽管对方摆出了攻击姿态，他仍拒绝后退。

He refused to ___back ___off despite the other man's aggressive posture.

意识到自己寡不敌众，那个恶霸最终决定退却。

Realising he was outnumbered, the bully finally decided to ___back ___off.