Complex sentence: Dwelling a year at a secret base on the mountain, even suffering from tuberculosis, he trained about a hundred guerrillas against the Japanese puppet regime of Manchukuo, those whom later constitutes of the third battalion of the Northeast Anti-Japanese United Army in 1936.
Split into simpler sentences: Dwelling a year at a secret base on the mountain, even suffering from tuberculosis, he trained approximately one hundred guerrillas against the Japanese puppet regime of Manchukuo. These guerrillas later constituted the third battalion of the Northeast Anti-Japanese United Army in 1936.