P104.which have long held ...

问题描述:

P104.which have long held ...
P104.which have long held that the Great wall and the dykes in the Netherlands are the only man-made structures visible from space,can breathe easily again.Wha’t the meaning of “can breathe easily again”

你的断句有问题,前面是个定语从句,主语你没给我们,谓语是can breathe easily again
所以没办法告诉你是什么意思