nail down

柯林斯詞典

1. PHRASAL VERB If you nail down something unknown or uncertain, you find out exactly what it is. 弄清
It would be useful if you could nail down the source of this tension. 如果你能弄清這種緊張情緒的根源，會是有用的。
2. PHRASAL VERB If you nail down an agreement, you manage to reach a firm agreement with a definite result. 確定 (協(xié)議)
The Secretary of State and his Russian counterpart met to try to nail down the elusive accord. 美國國務卿與俄羅斯外交部長會晤，試圖確定這項表述模糊的協(xié)議。