Complex sentence: Having developed an interest in flying, he obtained his flying certificate in 1911 and joined the Royal Naval Air Service Arthur Longmore, "From Sea to Sky" (Geoffrey Bles, London, 1946), Chapter II in 1912.
Split into simpler sentences: Having developed an interest in flying, he obtained his flying certificate in 1911. Longmore joined the Royal Naval Air Service Arthur Longmore, "From Sea to Sky" (Geoffrey Bles, London, 1946), Chapter II in 1912.