Complex sentence: The 7th Battalion was formed from the Indochinese in Tonkin on February 16,1916 and landed at Marseilles in September and underwent training at Frejus until April 1917.
Split into simpler sentences: The 7th Battalion was formed from the Vietnamese in Tonkin on February 16,1916 and landed at Marseilles in September. They underwent training at Frejus until April 1917.