Complex sentence: During the post-war boom of 1918-1920, the worldwide demand for Java sugar was high, creating many opportunities for sugar-mill owners and sugar brokers, but fortunes gained were easily lost in a couple of days.
Split into simpler sentences: During the post-war boom of 1918-1920, the worldwide demand for Java sugar was high, creating many opportunities for sugar-mill owners and sugar brokers. But fortunes gained were easily lost in a couple of days.