It has often been said that life is difficult as it isas it is 如何理解

It has often been said that life is difficult as it isas it is 如何理解 完成时的否定It has often been said这句话的否定是什么 it has been since.用法 It has been in my it is/has been= It's has been accepted it has long been assumed it's always been you(It has always been it has been可以缩写成it's been it's been.的全称是不是 it has been... What has been buried has often been buried well.如题 often hit has never been hit中文翻译是什么意思 He has often been there.不用完成时怎么说 It has been raining these days. It has been e()hot this week. it has long been known that it has since been rebuilt怎么翻译 英语翻译It has been proved that by carefully controlling the rate of cooling of the temperature,SA can find theglobal optimum.However,this requires infinite time.Fast annealing and very fast simulated re-annealing (VFSR) or adaptive simulated ann