The World Wildlife Fund has declared that global warming,a phenomenon that most scientists agree is caused by human beings' burning of fossil fuels,will create havoc among migratory birds by altering the environment in ways harmful to their habitats.
划线的句子 主干是,a phenomenon is caused by human beings' burning of fossil fuels
也就是说同位语可以是一个完整的句子吗?
同位语不应该是 N, a+N的形式吗?