HSK 4
Zhè kuǎn kōngtiáo fēicháng jiénéng.
This air conditioner is very energy-efficient.
HSK 6
Zhèngfǔ dàlì tuīguǎng jiénéng jiǎnpái.
The government vigorously promotes energy conservation and emission reduction.
HSK 7-9
Jiénéng dēngpào bǐ pǔtōng dēngpào shěngdiàn.
Energy-saving light bulbs use less electricity than regular ones.
