However, if the patent is likely to lose its usefulness in less than 17 years, amortization should be based on the shorter period of estimated usefullife.
然而，如果专利权可能在不到17年内就失去效用，摊销应以更短的预计存续期限为基。
2
With provision for the impairment of fixed assets, in the next period by deducting the book value after impairment and determine the remaining usefullife depreciation.
以计提减值准备的固定资产，在未来期间按扣除减值准备后的账面价值及尚可使用年限确定折旧额。
3
Article 14 the guarantee system of projection quality shall be practiced for the urban roads. The guarantee period shall be the project's reasonable usefullife stipulated in the design document.