我们在森林里发现了一连串的小瀑布。

We discovered a series of ___cascades in the forest.

瀑布般的水流从岩石上层层叠叠地落下。

The water fell from the rocks in a beautiful ___cascade.

经济危机引发了一系列连锁反应，最终影响了全球市场。

The economic crisis set off a ___cascade of reactions that ultimately affected global markets.