Complex sentence: She stood by in China during civil disturbances which threatened American lives and property and in September she visited Port Arthur and Darien on intelligence duty, then returned to her base at Cavite for overhaul.
Split into simpler sentences: She stood by in China during civil disturbances which threatened American lives and property. In September she visited Port Arthur and Darien on intelligence duty, then returned to her base at Cavite for overhaul.