Complex sentence: The 1950s saw the commencement of Hong Kong's 40 year rise to global eminence, during which time the Hong Kong Police tackled many issues that have challenged Hong Kong's stability.
Split into simpler sentences: The 1950s saw the commencement of Hong Kong's 40 year rise to global eminence. Throughout this period the Hong Kong Police has successfully tackled many issues that have challenged Hong Kong's stability.