我们必须为后代保护环境。

We must ___preserve the environment for future generations.

我们希望在改善设施的同时保护小镇的特色。

We want to ___preserve the character of the town while improving the facilities.

每个人都努力做一些事情来保护我们星球的健康是根本的必要条件。

It is a fundamental necessity for everybody to try to do something in order to ___preserve the health of our planet.