The most important thing_______we should pay attention to is the thing_______I have said.

A．which that

B． that which

C． which which

D．that that

锚喷支护维修方法主要有哪些？（）

A.更换支架

B.加固支架

C.补打锚杆或喷浆

D.改用砌碹支护

E.改用棚式支护