been

eg.Scientists think that there has been life on Earth for millions of years科学家认为生命存在于地球已经有几百万年了。have been done现在完成时的被动形式，表示已经被完成have been doing现在完成进行时，表示到现在为止仍然在进行。The work has been done.工作已经被完成了。强调结果They have been playing football for 3 hours.他们已经踢了3小时的足球了。可能还未结束。强调结果直接用have done现在完成时;强调过程或还未完成的动作行为用have been doing现在完成进行时。They have finished the work.They have been doing the work for a whole day.I have read the book.I have been reading the book for a week.have been(+-ing动词)：现在完成进行式例句与用法:I have been away from Paris for two weeks.我离开巴黎已经两星期了。Flowers soon faded when they have been cut.花剪下后很快就会枯萎。Had he not saved me, I might have been drowned.我可能溺死了，若非救了我。He is said to have been the richest man in Taiwan.据说他以前是台湾最有钱的人。She is said to have been an actress about twenty years ago.据说她在20年以前曾是一位女演员。