About "Siheyuan", a courtyard residence, which of the following choices are right?
A.
"Siheyuan" is known at home and abroad as main old Pekinese habitancy for generations.
B.
"Siheyuan" consists of the north house, south house, east and west wing houses, east and west corner houses.
C.
The principal room is built on the south-north axis, and two wing rooms are located on both sides of it.
D.
The family elders usually live in the wing rooms.