one of the first countries supporting（已经支持）
one of the first countries to recognize（正在意识到）
china was one of the first countries supporting the palestinian national liberation movement and to recognize the palestin liberation rganization as a legitimate government.
中国是最早支持巴勒斯坦民族解放运动的国家,并且是第一个正在意识到巴勒斯坦解放组织是合法政府的国家.这里 supporting 和to recognize 非谓语做什么？补主语？都是后置定语