It’s very dangerous to these viruses without any protection.A. be exposed toB. expose to

问题补充：

It’s very dangerous to these viruses without any protection.

A. be exposed to

B. expose to

C. expose

D. be exposing to

答案：

(答案→)A. be exposed to

B. expose to

C. expose

D. be exposing to

解析：句意：在没有任何保护措施的情况下，暴露于病毒下是非常危险的。是“被暴露”，故用被动语态，选A。