when your order____ ,we will send you another e-mail.

问题描述:

when your order____ ,we will send you another e-mail.
A ships Bwill ship C has been shipped D has shiped
我知道这道题肯定要选C 被动语态,但是为什么要用完成时态呢?如果说is shipped

因为“被装上船”也许不是一个动作就能完成,而是需要装一段时间,所以用现在完成时.不能说is shipped.