我想要一块蛋糕。
Wǒ xiǎngyào yí kuài dàngāo.
I'd like one piece of cake.
给我一块钱。
Gěi wǒ yí kuài qián.
Give me one dollar.
这个多少块钱?
Zhège duōshao kuài qián?
How much is this?