The party lastnight was ____   success; we sang and danced until it came to ___ end at twelve.    [    ]

A. /;/    

B. a;the    

C. the; an  

D. a;an

炉甘石的主要化学成分是

A．硫化汞

B．碳酸锌

C．含水硫酸钙

D．含水硅酸镁

E．二硫化二砷