The pilot tried to control the plane, but it suddenly nose-dived.

nose-dived 是动词 nose-dive 的过去式。nose 指"飞机头部"，dive 意思是"俯冲、下潜"。nose-dive 字面意思是"头部向下俯冲"，用来描述飞机突然急剧下降的动作。