My gaze kept returning to the thundersheet and I felt a nervous urge to rush up to it and strike it.

我的目光不停地回到雷雨席上，我有一种紧张的冲动想冲上去攻击它。

A thundersheet, in case you don't know, is a thin piece of metal, a couple of yards square, which when shaken produces a mysterious rumbling noise not unlike thunder.

雷雨片，如果你不知道的话，是一块薄金属，几码见方，当它被摇动时会产生一种神秘的隆隆声， 这与雷声不同。