It _（be) two years since he left school.为什么不能填have been呢?

It _（be) two years since he left school.答案上是is,但是为什么呢? It _（be) two years since he left school.为什么不能填have been呢? It will be two years before we meet again 翻译 The teacher's office ___（be) very small two years ago.The teacher's office ___（be) very small two years ago.I was ____(surprise) to see him in the street.It would be fine____ (travel) inchina.Bill ____(study) in Canada for two years.Every boy ___ It is hoped that after two years,we have the same love.是啥子意思_? Lucy has been away from home for two years.（改同意句） It's two years since Lucy________. Lucy has been away from home for two years 句型转换 it's two years since Lucy（ ）（） I have been learning English for two years.=It's two years _____ I _____ to learn English. it's such an interesting book.i have bought it for two years错误的地方 It's about two hundreds years old?这句英语那里有错误?错了,应该是It's about two hundreds years old. She says it's be two month.改错 Be quick!It's time _(介词)class in two year 和 in two year's time区别Our school will be more beatiful ______A.in two year B.after two year's timeC.two years time D.in two years' time选哪一个,理由, It`s Two Two Too the total ages of two boys is seventeen.what will it be in six years' time? It was proposed that the president (should) be elected for a period of two years.translate It _(be)five years since we last saw each other. 英语 同义句（用现在完成时）Tom's brother left hometown two years ago.Tom's boreher _____ _____ ______ ______ his hometown for two years.It ______　______ two years _______ Tom's brother left his hometown