1 One-handed bench press!
2 supine straight arm pull-ups
3 dumbbell flat bench press!
Four dumbbell birds
Summary: Do 15RM for each movement, and choose the weight of dumbbells according to your physical fitness. (5kg, 6kg, 8kg, etc. ) Choose the weight of dumbbells that you can bear moderately, and don't pursue the weight of dumbbells excessively!