环保外文广告词可以有多种表达方式，以下是一些建议：

Love is boundless, green is boundless.

Please protect every tree and bush.

Take care of flowers.

Don't tread grass, not picking flowers.

Keep our nature healthy, 'cause it will make us wealthy.

Reduce wastes and recycle, you will be fed.

Protect the earth's environment -- the homeland of all mankind.

We only have one Earth.

Love our environment means loving ourselves.

Clear sky, clean water, green mountains, and beautiful rivers.

The heart is the destiny of human beings and the oasis of life - China's environmental.

Reduce waste to protect our environment.

I do not pluck flowers! （好看花儿我不摘）

Treasure the tables and chairs! （爱护桌椅）

Save water!

The earth is cleaner, we live a little more comfortably.

Welcome green resources, send back air pollution.

Green environment, purifying the mind.

Clear the road, one of the sewage.

Plant a tree, green a sky.

这些广告词旨在提醒人们保护环境的重要性，并鼓励大家从日常生活中做起，共同创造一个更绿色、更美好的世界。您可以根据具体场合和目标受众选择合适的广告词。