Complex sentence: The Indonesian National Revolution was an armed conflict and diplomatic struggle between Indonesia and the Netherlands; there was also an internal revolution that took place between the time of Indonesia's declaration of independence in 1945 and the Netherlands' recognition of the country in 1949.
Split into simpler sentences: The Indonesian National Revolution was an armed conflict and diplomatic struggle between Indonesia and the Netherlands; it also included an internal revolution. The struggle took place between the time of Indonesia's declaration of independence in 1945 and the Netherlands' recognition of the country in 1949.