How did she get infected?Because she------the

问题描述:

How did she get infected?Because she------the
How did she get infected?
Because she------the viruses whitout any protection .
A had exposed to B had been exposed to
选B 为什么呐?

当然是选择a了 因为她在那时(过去时间点)已经接触到病毒了.过去的一段时间对过去时间点造成了影响.
属于过去完成时 exposed过去分词