We need to stay alert all the time.

我们需要时时刻刻保持警惕。

As a skirmisher, he must always stay alert.

作为一名散兵，他必须时刻保持警惕。

The driver needs to stay alert at all times.

驾驶员需要时刻保持注意力。

A prison guard needs to stay alert at all times.

狱警需要时刻保持警惕。

We should stay alert to any suspicious activities.

我们应该对任何可疑活动保持警惕。

When walking in the forest, you need to stay alert.

在森林里散步时要保持警惕。

A signaller must always stay alert to avoid accidents.

信号员必须时刻保持警惕以避免事故。

When traveling in unfamiliar places, never be too careful, stay alert.

在陌生的地方旅行时，小心驶得万年船，保持警惕。

They didn't stay alert in case the car needed to hand control back to them.

他们没有时刻保持警惕以防车把控制权交还给他们。

The male must stay alert. There are hunters here who would snatch his young.

妈妈必须保持警惕。猎人正在觑觎着孩子。