（ ）two years（ ）she became a college student.A.It was ;when B.It is;when C.It was;since D.It is ;since求答案和选择原因
问题描述：
（ ）two years（ ）she became a college student.
A.It was ;when B.It is;when C.It was;since D.It is ;since
求答案和选择原因
答
D 自从她上大学已经两年了 two years It was since she became a college student 两年以后,她就成为了一名大学生 It was two years
答
A It's +一段时间+since。。。相当于 It has been +时间+since 。。。表示的意思。
答
D.It is ;since
在主句表示多长时间时,可以用一般现在时代替现在完成,此处就是用it is 代it has been,since本来是现在完成时的时间标志语.