PHRASE
在…的旗幟下；為了…的事業（或信仰）
If someone does something under the banner of a particular cause, idea, or belief, they do it saying that they support that cause, idea, or belief.
例句
All countries march as one nation under the banner of friendship.
所有國家在友誼的旗幟下團結一致，共同前進。
Under the banner of education, we herd our children from ballet to basketball and back again.
打著教育的旗號，我們趕鴨子上架似的讓孩子從芭蕾到籃球，不停地學這個學那個。