There was a sign telling motorists to slow down.

有一个让汽车司机减速的指示牌。

《牛津词典》

Another universal warning sign is when fluctuations in the system slow down.

另一个通用的预警信号是，系统中的变动速度慢下来。

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"Reckless drivers will slow down when they see a student driver sign," the company advertised.

“鲁莽的驾驶者当他们看到学车的标志时会放慢速度。”公司建议说。

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Fires in the Rockies and the Pacific Northwest show little sign of the usual September slow-down, and firefighting resources nationwide have been stretched thin.

NPR: No End in Sight for Western Fire Season