death knell

1. N-SING If you say that something sounds the death knell for a particular person or thing, you mean it will cause that person or thing to fail, end, or cease to exist. 导致终结的原因[usu 'the' N 'for/of' n]

The tax increase sounded the death knell for the business. 税收的增长预示着这项生意的终结。