问题补充：
—How did she get infected?
—She the viruses without any protection.
A. exposed to
B. had exposed to
C. was exposed to
D. has exposed to
答案：
A. exposed to
B. had exposed to
(答案→)C. was exposed to
D. has exposed to
解析：考查固定词组。固定词组be exposed to…遭受..暴露…句意：—她怎么受到感染的？—她没有任何的保护，直接暴露在病毒之下。故C正确。
