A cache that expires too often can result in unnecessary performance degradation; therefore cache lifetime values are also important to tune.
太频繁过期的缓存会导致不必要的性能下降；因此，优化缓存生存期值也是非常重要的。
2
They are also a function of a peculiar labour market with lifetime employment, a wage system based on seniority rather than performance, and little job mobility among managers.
同时这种薪酬制度也有助于维护该国特有的讲究论资排辈和缺乏流动性的终身雇佣制为基础的劳动力市场。
3
Relatively low levels of exposure can reduce their IQ scores, cause learning disabilities, poor school performance, and violent behaviour, all of which may contribute to reduced lifetime earnings.