Beijing, the capital of China, is one of __________ cities in the world.

What’s this in English? —It’s ____ eraser.

Can you tell me to live a low-carbon(低碳) life? — OK. Use both sides of the paper. Don’t use plastic bags or disposable goods(一次性用品).

You ______ be polite to the old man.

Hei Longjiang is a pretty province __________ a river __________ through it.[ ]