Frequently Asked Questions.
Example: Greeting your teacher in Mandarin/Putonghua
(open class ) teacher says - "Shanke"
student says teacher Hallo - "*Laoshir Hao"
(close class) teacher says - "Shake"
student says - "Xie Xie *Laoshir, *Laoshir Zaijian" (thank you teacher; teacher goodbye)
*PS: Remember to replace "Laoshir" with teachers title or rank)