苦口婆心，汉语成语，拼音kǔ kǒu pó xīn，善意的又不厌其烦地劝导某人。
因为苦口婆心的说教毕竟不是万能良药。
The sermon because of a tender remonstrance is not omnipotent good medicine after all.
即使你苦口婆心地批评他，也改变不了他的个性。
You can criticise him until you're blue in the face, but you'll never change his personality.
我能做的只是苦口婆心地教育孩子们从我的错误中吸取教训。
Here is where I beg, in cloying tones, that we teach the children to learn from these mistakes.
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