Complex sentence: However, American troops found few enemies to attack and found themselves constantly harassed by Lukban's guerillas, untill two prisoners revealed the location of Lukban's secret headquarters along the Caducan river.
Split into simpler sentences: However, American troops found few enemies to attack and found themselves constantly harassed by Lukban's guerillas. But two prisoners revealed the location of Lukban's secret headquarters along the Caducan river.