sentences:  From July 4, 1938, the Mongolia Garrison Army came under the administrative jurisdiction of the North China Area Army.In January 1939 the Cavalry Group was added, consisting of the 1st Cavalry Brigade and 4th Cavalry Brigade.In December 1942, the 4th Cavalry Brigade was sent to the Twelfth Army and the remainder of the Cavalry Group was converted into the 3rd Tank Division.