老师提醒学生们要保持抬头姿势并看着黑板。

The teacher reminded the students to keep their ___heads up and look at the blackboard.

经理提前给我们发了个提醒，说下周会有重要检查。

The manager gave us a ___heads-up about the important inspection next week.

记得提前告诉我你要迟到，好让我有个准备。

Remember to ___give me a heads-up if you're going to be late.