There were 15 minutes between the first air raid alert and the sounding of the all-clear signal.

从第一个空袭警报到警报解除号音其间有15分钟。

《柯林斯英汉双解大词典》

Steinbruck told the Bild am Sonntag newspaper: "Any all-clear signal would be false."

施泰因布吕克告诉德国图片报：“任何解除警报的信号都是假的。”

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The attendants set up a barrier to the cockpit and give us an all-clear signal to open the door, as we don't have a separate bathroom and have to use the same one as everyone else.

乘务员就会在驾驶舱前拉开一道屏障，然后给我们发送一个无人信号才能使用。

youdao

Earlier in the day, the Fed got what amounts to an all-clear signal to lower rates without having to worry about near-term inflationary consequences.

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This is a clear signal that businesses are reluctant to hire in large enough numbers to bring down this all-important number.

FORBES: The Stock Market And Recessions