Three years has past.为什么“three years”可以看做单数?

为什么是in the past three years而不是over the past three years In the past three years in the past three years 可以用于一般过去时吗? Tom has( )for three years three years has/have passed three years You___a lot in the past three years. he has left since three years ago可以用吗 He has died three years ago.如果错的话,为什么终止性动词可以用于现在完成时? nearly three years ( )has passed 还是 have past since i studie The young man has written three bopks in the past two years. He has been dead for three years