As the train doors opened, there was a rumble of thunder overhead.

车门打开了，空中传来隆隆的雷声。

Even the growing number of pipes made from corrosion-resistant materials are not immune to problems: urbanisation, with more traffic thundering overhead, can accelerate the rate at which cracks form.

即使越来越多的由耐腐蚀材料制成的管道也无法避免问题：城市化、车流的增多会加速裂缝的形成速度。