—I could have arrived much earlier, but I ____ in the traffic.

—What a pity![ ]

A. would be caught

B. was caught

C. has been caught

D. had been caught

关于阵发性睡眠性血红蛋白尿发病机制叙述正确的是（）

A.红细胞对补体激活敏感度下降

B.GPI锚连膜蛋白过度表达

C.补体适宜pH为8.0～9.0

D.CD55和CD59因子与发病关系最密切

E.夜间发病为pH升高所致