关头 (guān tóu): Critical moment (Noun) — Meaning & Stroke Order

At the critical moment of the negotiation, he proposed a compromise acceptable to both parties.

Don't you realize that this is the life-or-death moment that determines the success or failure of the project?

At the critical moment of the exam, he stayed calm and finished the questions smoothly.

Quick, give me the spare parts. This is the critical moment for repairing the machine!