linchpin
n
1 pin passed through the end of an axle to keep the wheel in position 轮辖; 制轮楔.
2 (fig 比喻) person or thing that is vital to an organization, plan, etc (组织、 计画等中)关键性的人或事物
Controlling wages is the linchpin of the Government'spolicies. 控制工资是政府政策的关键.
🗣️ 情景例句
Sorry, I have to say good-bye.
我不得不说再见了。
But you have to pay 5% commission on this money exchange.
但兑换这笔外币,您得另外付5%的手续费。
One day a letter from my father arrived at the school, asking for a teacher for me.