求助这句话是么个意思：It has been tracked for Impact Factor by Thomson

求助这句话是么个意思：It has been tracked for Impact Factor by Thomson It has been increased by a factor of 4.为什么这句要使用现在完成时的“被动时态”? It has been increased by a factor of 4 since 1995.怎么翻译? It has been five years since he has left for beijing这句话对不对啊 告诉我下这句话的意思This program has been damaged ,possibly by a bad s 英语语法求助Mr.D has been worried all week.这句话是什么时态?has been worri it has been the case for a long time that...这句话正确吗? 英语翻译邓露《Development of dynamic impact factor for performance My grandfather has been dead for many years.这句话为什么用has been的 "Life has become richer by the love that has been lost."这句话该 这句话有几个助动词The work has been done by tom .has 和 been哪个是助动词 为啥 Your message has been received这句话什么意思