Li Yundi began to learn the piano _____ the age of four and took part _____ the 14th Chopin International Piano Competition in 2000.[ ]

While I was walking along the lake, I saw some fish _____out of the water.

Could you tell me something about Zheng He?–Sure. He was a Ming Dynasty explorer __ the Chinese people are proud of.

He looks sad. Let’s ___________________.

One hundred yuan for a bowl of noodles, you ________ be joking!