大変お世話になりました。
承蒙您的关照。
承蒙关照，不胜感激。
Thank you very much for all you have done.
You've been really good to me.
You have been really good to me.
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大変， 大へん， たいへん
1. very, greatly, terribly, awfully
2. immense, enormous, great
3. serious, grave, dreadful, terrible
4. difficult, hard, challenging
5. major incident, disaster
非常、极其、非常严重、极其糟糕；巨大、庞大；严重、严峻、可怕、糟糕；困难的、艰难的、具有挑战性的；重大事件、灾难
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お世話になる， おせわになる
1. to receive favor, to receive assistance, to receive help, to be looked after, to be taken care of, to become dependent (on), to become much obliged (to someone), to become indebted
蒙恩惠，得帮助，受援助，受照料，受关怀，依赖(于)，感激(于某人)，欠人情