Beijing was freed from warlord control in 1928. using the map key, determine how long, at the most, beijing's freedom lasted and why. _

After the 1928 liberation, Beijing became free up to the second Japanese Sino war that began in 1937; it was elected as the sitting government in China and ruled as a puppet government that was occupied by Japanese.

In 1937, all-out Japanese in China launched an invasion, and in 1938, the Japanese had already controlled a large part of China. They then forced complicated alliance among the Jiang’s and Mao’s and put on hold their differences temporarily and focused on uniting the Japanese.

it's not the readmission