Complex sentence: The 7th and 15th Soviet Armies advancing behind collapsing White Russian forces continued to attack fortified positions at the Estonian border near Narva, first clashes took place on Luga River on 16 November, starting final battles of war where 120,000 Soviets faced 40,000 Estonians.
Split into simpler sentences: The 7th and 15th Soviet Armies advancing behind the collapsing White Russian forces continued to attack fortified positions along the Estonian border near Narva. The first clashes took place on the Luga River on 16 November, starting the final battles of war with 120,000 Soviets facing just 40,000 Estonians.