你必须保持冷静，待在那里直到震动停止。

You must keep calm and stay there until the shaking stops.

youdao

如果你想成为一名像刘翔一样优秀的运动员，你必须保持身体健康，准备好经受大量刻苦的训练。

If you want to be an excellent runner like Liu Xiang, you must be in good health and be prepared to go through much hard work.

youdao

你必须保持清醒和控制力。

You have to be lucid and in control.

youdao

You have to remain celibate and, as we will see in the coming week, this is important to Milton. You have to remain sober, and you must eat vegetarian .

你必须独自生活，我们会在下周看到，这对弥尔顿很重要，你必须保持冷静，你还必须吃素。

耶鲁公开课 - 弥尔顿课程节选

you have to be in your top shape,

你必须保持最好的身材状态，

保持身材的理由 - SpeakingMax英语口语达人

So who the sender is, so maybe you could keep track of just who your most frequent correspondents are and if you keep seeing the same personfrom person X or person Y coming into your inbox and clearlyI like having a dialog with these people or have to for work, that might in fact bubble up in your inbox.

谁是发送者，你可能会保留最近跟你联系最频繁的人,如果你发现某某人频繁发送邮件给你,这说明你喜欢和这些人保持联系,可能因工作的原因必须保持联系,那么该邮件就有可能，上升到你邮件的最上方。

哈佛公开课 - 计算机科学课程节选