可抑制MAC形成的补体膜调节因子是()
A.S蛋白
B.H因子
C.DAF
D.MCP
E.HRF
参考答案:E
解析:HRF可以阻止同种细胞MAC形成。
We have been good friends ________ we joined the same ping-pong team. [ ]
A.after
B. before
C. since
D. until
露点