— Would you like to tell me         ?

— Sure. Practice makes perfect.

A．how can I study English well

B．why do you learn English well

C．how I can study English well

D．why I learn English well

可抑制MAC髟成的补体膜调节因子是( )

A．S蛋白
B．H因子
C．DAF
D．MCP
E．HRP