The old man ______live with his wife, but now he ______alone after she died.              [ ]

A. used to; is used to live          

B. used to; is used to living              

C. was used to; used to live        

D. is used to; is used to live

α-酮酸氧化脱羧酶的辅酶是

A．VitB₁
B．VitB₆
C．VitB₁₂
D．VitPP