wǒ yào jì yì fēng xìn .
I would like to send a letter.
guà hào xìn hái shì píng xìn ?
Is it a registered or regular mail?
jì dào měi guó yào duō shǎo qián ?
How much does it cost to ship to the United States?
mǎi wǔ zhāng bā máo de yóu piào .
I want to buy five 80-cents stamps.