His presentation went disastrously wrong when he misquoted all the key figures.

disastrously 是形容词 disastrous 的副词形式，由名词 disaster（灾难）加形容词后缀 -ous 构成 disastrous（灾难性的），再加副词后缀 -ly 构成副词。意思是"灾难性地、极其糟糕地"，用来强调事情出错的程度非常严重。