Complex sentence: The alliance was renewed and strengthened in 1905 and 1911, but declined during World War One and finally expired in 1921, much to the regret of Sir Charles Eliot, and the pleasure of the United States and China.
Split into simpler sentences: The alliance was renewed and strengthened in 1905 and 1911. The treaty expired in 1921, much to the regret of Sir Charles Eliot, and the pleasure of the United States and China.