—I________ some new CDs.

—When_________ you_________ them?      

—Yesterday morning.     [ ]

A. buy; did; buy    

B. buy; do; buy    

C. have bought; will; buy

D. have bought; did; buy

早期诊断化脓性关节炎最有价值的是

A．X线片
B．血常规
C．关节穿刺液检查
D．临床表现
E．CT或MRl