The drawing is as follows:
(1)35+45=80 (unit)
Answer: In July and August, Gree air conditioners** *80 units sold;
(2) July: 24+35+314=103 (units)
August: 12+45+38+20=115 (Taiwan)
115-103=12 (Taiwan)
Answer: There were more air conditioners sold in August, 12 more;
(3 ) Information can be obtained from the statistical chart: Among the four types of air conditioners sold, Gree air conditioners have the largest sales volume, indicating that Gree air conditioners are more popular.