Best for beginners
If you live in China, you have probably seen something similar to this in the last year or so. My snapshots are from this morning.
What is this about? The photo on the left provides detail. The photo on the right provides context. (Click to make the photos larger, to make the small text legible.)
What two words does Chinese turn into this "efficiency contraction," as shown in the bottom of the frame? -- 环保。When starting out learning the language in a practical way, beyond the textbook, these things can throw you for a loop because they often are not in the dictionary. (Click to see the answer.)
And here's the give-away in pictures in case you are still wondering.