Question

---I do believe the scientific explanation that when a tomb is opened, the fresh air disturbs the viruses inside it. What about you?
---So do I. If ______ in, the disturbed viruses may cause illness or even death.

1. A.
   breathing
2. B.
   breathed
3. C.
   being breathed
4. D.
   to breathe

Answer 1

B
考查条件状语从句的省略。当状语从句的主语和主句主语一致，并含有be动词时，从句的主语和be动词可以省略。If _______ in, the disturbed viruses may cause illness or even death.补充完整应是：if the disturbed viruses are breathed in, the disturbed viruses may cause illness or even death.所以选B。