他的足迹印在雪地上。

His ___footprints are left in the snow.

沙滩上留下了许多脚印。

Many ___footprints are left on the beach.

沙滩上留下了孩子们的脚印。

The children's ___footprints were left on the sandy beach.

我们的数字足迹对环境的影响比想象中更大。

Our digital ___footprints have a bigger impact on the environment than we realize.