For unusual luggage, guests or vehicles remain on high alert.

对异常的的行李、客人或车辆保持高度警惕。

youdao

The cave fish, on the other hand, remain on high alert, patrolling their habitats even after hours.

而另一方面，穴居鱼仍然保持高度警惕，三更半夜还在居住的地方游来游去。

youdao

Key installations in Kabul and around the country remain on high alert as a result of the assault on the hotel.

对酒店的攻击事件使喀布尔和全国各地的主要设施保持高度警戒。

youdao

Dr.Chan said all countries should immediately activate their pandemic preparedness plans and countries should remain on high alert for unusual outbreaks of influenza-like illness and severe pneumonia.

VOA: standard.2009.04.29

Speaking to local media, Pakistani Interior Minister Rehman Malik said intelligence agencies had expected attacks on security sites in the country and that authorities will remain on high-alert.

VOA: standard.2009.10.15

As a result, it is safe to say that traders are likely to remain on high alert for any and all economic news from April and beyond.

FORBES: The Jobs Report Is NOT Pushing the Markets Higher Today

Prime Minister Chung Hong-won called on residents of Yeonpyeong to remain calm and for the military to be on "high alert" in the face of provocation.

BBC: South Korean prime minister visits border island