Just outside the limits of Siwa, tremendous and imposing sand dunes linger, constantly threatening to advance.

巨大而壮观的沙丘，就徘徊在锡瓦的边界外，时刻威胁着前进。

They are also narrowly trained for specific applications and thus fail badly when outside the limits of that training or in response to " spoofing" by adversaries.

它们还为特定的应用进行了严格的训练，所以当情况超出了训练的范围或者应对敌方的“诈术”时，它们会败得很惨。

But in the video, officers are seeing striking Nichols repeatedly during the encounter in a manner that law enforcement analysts have described as well outside the limits of police training.

但在视频里，人们看到警察在执法过程中不断殴打尼科尔斯，执法分析人士认为这种行为超出了警察的职权范围。