那条大狗凶猛地咆哮着，吓得小孩立刻躲到了妈妈身后。

The large dog growled ___fearsomely, making the child immediately hide behind his mother.

那个拳击手出拳极其迅猛，对手根本无法招架。

The boxer punched ___fearsomely fast, leaving his opponent no chance to defend.