Politeness is universal! The word for "please" is 请 (qǐng). You use it when making a request, like 请进 (qǐng jìn) - Please come in. "Thank you" is 谢谢 (xièxie). To be more grateful, you can say 非常感谢 (fēicháng gǎnxiè) - Thank you very much. The response to "thank you" is 不客气 (bú kèqi), which means "You're welcome."