________a pianist，I had to sing solo.Much to my relief，my performance was fully appreciated by the

audience.[ ]

A．Lack  

B．Lacking of  

C．Lacking  

D．Lacked in

不含有芳基醚结构的药物是（）

A.胺碘酮

B.美托洛尔

C.美西律

D.普萘洛尔

E.普罗帕酮