谢谢老师 is the most common way to say "thank you" to a teacher in Chinese. This phrase pterally means "thank teacher," with 老师 (lǎoshī) being the word for "teacher" and 谢谢 (xièxie) being the word for "thank you."

The phrase 谢谢 comes from the verb 谢许 (xièxǔ), which means "to thank" or "to express gratitude." This verb comes from the Chinese character 谢, which is a combination of the characters 言 (yán), meaning "speech," and 心 (xīn), meaning "heart." Together, these characters suggest the idea of thanking someone from the bottom of one's heart.

Here are a few example sentences using 谢谢老师:

谢谢老师给我提供帮助。 (xièxie lǎoshī gěi wǒ tígōng bāngzhù) - Thank you, teacher, for providing help.
谢谢老师指导我学习。 (xièxie lǎoshī zhǐdǎo wǒ xuéxí) - Thank you, teacher, for guiding me in my studies.
谢谢老师教我知识。 (xièxie lǎoshī jiāo wǒ zhīshi) - Thank you, teacher, for teaching me knowledge.