求翻译：但是，由于现有的低保制度水平太低，2011年上海城镇居民最低生活保障标准仅为每人每月505元，所以除了低保家庭外，很有很多刚刚高于低保线但是生活的确很紧张的低收入群体不能享受到免单的政策。是什么意思？

However, due to the low level of the existing system of subsistence allowances, the minimum living standard of the 2011 Shanghai urban residents was only 505 yuan per person per month, so in addition to low family, very many just above the Poverty Line but that life is indeed tense low-income groups

However, due to the existing system of low-level is too low, 2011 Shanghai ensure a minimum standard of living cities and towns only for $505 per person per month, in addition to the low security outside the family, there is a lot more than just low life insurance online but it is indeed a tense, lo

But, because existing guarantees the system level too to be low lowly, in 2011 the Shanghai cities inhabitant lowest social security standard is only each human of each month of 505 Yuan, therefore besides guarantees the family lowly, but had very much very many just is higher than guarantees the li

However, due to the low level of existing social security system too, 2011 Shanghai urban resident's minimum living security standards only 505 dollars a month per person, in addition to poor families, there are very many lives just above the low-line but was very nervous of low income groups do not

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