harp on one (/the same) string; play the same old tune(/story/theme /refrain); sing the same old song(/tune) ❍ 你总是～，有谁欣赏呢？ You’re always harping on the same string. Who’d like to appreciate it?/现在他又开始～了。Now he’s started on his hobbyhorse.
旧调重弹
harp on the same string; play the same old tune; rehash old ideas
旧调重弹旧（老）jiù diào chónɡ tán
陈旧的曲调又弹奏了一遍。比喻把过时的理论和观点重新拿出来，说得还是老一套。harp on the same old tunes, play back the same old story, play the same old tune, sing the old song again, beat over the old ground