这些热带鱼只能在淡水中生存。

These tropical fish thrive only in ___fresh ___water.

在苏格兰高地，你会发现许多湖泊充满了清澈的淡水。

In the Scottish Highlands, you'll find many lochs filled with crystal-clear ___fresh ___water.

保护我们的淡水资源对可持续发展至关重要。

Conserving our ___fresh ___water resources is critical for sustainable development.