Call me when the fog set in. Sound regulation whistle, attend to echo sounding and start radar at an interval not more than 20 minutes.

下雾时要叫我，鸣放汽笛，动用测深仪，启动一次雷达不要超过20分钟。

youdao

The Tigers, who will face London Irish in the final at Twickenham on 16 May, set out determined to finish this one inside regulation time and they dominated from the opening whistle.

BBC: Leicester 24-10 Bath

Since the dawn of mutual fund regulation in the United States (1940) only one Compliance Director of a mutual fund company has ever blown the whistle on his employer.

FORBES: Confessions of an SEC Whistleblower