---Can you come on Monday or Tuesday, John?

---I’m afraid _______ day is possible. I will be very busy on those two days.

A．every

B．some

C．either

D．neither

导致心包炎最常见的致病菌是

A．金黄色葡萄球菌
B．军团菌
C．结核杆菌
D．支原体
E．霉菌