You use largely to say that a statement is not completely true but is mostly true.
mainly
The fund is largely financed through government borrowing.
这项基金基本上靠政府借款资助。
I largely work with people who already are motivated.
我总是与积极性高的人一起工作。
Largely is used to introduce the main reason for a particular event or situation.
Retail sales dipped 6/10ths of a per cent last month, largely because Americans were buying fewer cars.
零售额上个月下降了0.6,主要是由于美国人购买的汽车量开始减少。
The French empire had expanded, largely through military conquest.
法兰西帝国得以扩张,主要是通过军事征服。