我知道it作为人称代词用可以用来指代单数。但是在这句话中（见下）却是指代复数，这是为什么呢？
eg：Newspapers have two great advantages over television. They can be used by men as barriers against their wives. It is still the only effective screen against the morning features of the loved one......
They用来指newspapers，it也用来指newspapers吗？
问了豆包： “it is still the only effective screen...” 时，是把报纸作为一种具有特定属性（作为遮挡物）的抽象概念来描述，强调其在特定情境下的独特功能，这种用法在一定程度上超越了常规的语法数的一致原则，更侧重于表达一种抽象的、整体性的概念或功能。
感谢老师的解答分享~~
