it代替前面提到的可数名词单数，或者不可数名词；they代替前面提到的复数名词；如果同时指两种完全不同的名词，比如“空气和玻璃”，则为they。此处与一般名词一样处理。注意不可数名词无复数形式。

相关介绍

They decided to base the new company in York.

他们决定将新成立的公司总部设在约克郡。

They won by a single goal after extra time.

他们在加时赛中仅踢进一球即获胜。

She lost it, just as I said she would.

我就说了吧，她把它丢了。