be content to stay mediocre; be (/rest) content with being the second best (/middling/commonplace); be resigned to mediocrity; rest content with remaining mid-stream without making further advance
? 我們一定要樹立雄心，堅(jiān)決克服掉～的思想。We should have lofty ambitions and resolutely get rid of the idea of being content to stay mediocre.
甘居中游
be resigned to mediocrity;be content with the middling state
甘居中游ɡān jū zhōnɡ yóu
比喻心甘情愿地處于中等地位。be content with the second best, resign oneself to a state of mediocrity, be content to stay mediocre