再不 … 就 … 了 (last chance)

"If we don't go now…"

• again / then再zàinot不bù + Verb + then / just就jiù … (completed / change)了le = "if (we) don't … now/soon, then …".
• again / then再zàinot不bùto walk走zǒuthen / just就jiùevening晚wǎn(completed / change)了le = "if we don't leave now, we'll be late."
• It warns that a last chance is closing.

again / then再zàinot不bù + Verb，then / just就jiù + Consequence + (completed / change)了le

• again / then再zàinot不bù…then / just就jiù…(completed / change)了le presses for action before it's too late.

if … not now再不zài bùleave走zǒuthen就jiùlate晚wǎn了le。

• again / then再zàinot不bùto walk走zǒuthen / just就jiùevening晚wǎn(completed / change)了le = "if we don't leave now, we'll be late."

Recap

Read the full reference: HSK 5 grammar — Adverbs.