Basic modeling
TAB: changes between edit mode and object mode. Obviously, object is for whole object, edit to edit the object.
CTRL+TAB: allows to change between vertex, edge or face edition mode.
Subsurface is here:

TAB: changes between edit mode and object mode. Obviously, object is for whole object, edit to edit the object.
CTRL+TAB: allows to change between vertex, edge or face edition mode.
Subsurface is here:
