formerly是时间状语吗

是时间状语，例如：

1、I learnt that the house had formerly been an inn.我得知这座房子以前是家客栈。

2、Many products formerly made of metal now are made of plastic.以前用金属制造的许多产品现在都用所料制造了。

3、formerly， sea power gave big nations influence over others.以前海军的力量能使强国影响其它国家。