Complex sentence: On 29 March 1970, the North Vietnamese launched an offensive against the Cambodian army with documents uncovered from the Soviet archives revealing that the invasion was launched at the explicit request of the Khmer Rouge following negotiations with Nuon Chea.
Split into simpler sentences: On 29 March 1970, the North Vietnamese launched an offensive against the Cambodian army. Documents uncovered from the Soviet archives revealed that the invasion was launched at the explicit request of the Khmer Rouge following negotiations with Nuon Chea.