重点讲解：

1.is critical to是至关重要的
The answer to this question is critical to success of the user interface.
这个问题的答案对于用户界面的成功是至关重要的c]hO^8U@dM。

2.pay back偿还；报答

Microfinance efforts have shown that the poor are credit-worthy and pay back their loans despite not having assets or working capital.
微型金融方面的实践显示，穷人有信用，虽然不具备资产或运转资本，但他们会偿还贷款%ApE=cNthrjl4。