Complex sentence: The Singapore strategy was a strategy of the British Empire between 1919 and 1941 to deter or defeat aggression by the Empire of Japan through basing a fleet of the British Royal Navy at Singapore.
Split into simpler sentences: The Singapore strategy was a strategy of the British Empire between 1919 and 1941. It was a series of war plans that evolved over a twenty year period to deter or defeat aggression by the Empire of Japan by basing a fleet of the Royal Navy at Singapore.