guī / gēn / jiū / dǐ / zhè / cì / shī / bài / shì / yīn / wéi / zhǔn / bèi / gōng / zuò / zuò / de / bù / gòu / chōng / fèn

归根究底，这次失败是因为准备工作做得不够充分。

In the final analysis, this failure was caused by inadequate preparation.