紧要关头jǐn yào guān tóu
the crucial moment;the critical juncture
❍ 他在～接到上级的指示，转入地下。At the crucial moment he got the instruction from the higher authorities and went underground.
紧要关头jǐn yào ɡuān tóu
紧急而重要的关键时刻。critical moment, crucial, the critical juncture, in a pinch
土层