题目内容：
A．overuse face masksB．deal with the mask problem seriously
C．rub their faces and noses in the subway
D．protest against the mask guidelines
E．help protect people from being attacked by a flu
F．announce the results of their mask research
根据上篇材料和选项回答题：
The scientists are trying to find out if masks may or may not __________．
参考答案：
答案解析：