 Complete the following phrase:  Mao had a younger brother, Mao Yingchu Chinese: , who was born in 1911. He had a similar military career as his older brother, becoming a pilot in the Nationalist Air Force of China and rising to the position of commanding officer of the 23rd Pursuit Squadron of 4th Pursuit Group of the Chinese Air Force by 1937. He saw combat at the Battle of Shanghai, Nanking, 