—  Did Jack come back early last night?

— Yes. It was not yet eight o'clock ______ he got home.[ ]

A. before    

B. when  

C. that  

D. until

美国药典

A．缩写是USP

B．缩写是PUS

C．现行版本是29版

D．现行版本是28版

E．与NF合并出版