问题补充:
We are sure everything here by the time you come back from abroad in a few years.
A. had changed
B. will have changed
C. had been changed
D. will have been changed
答案:
A. had changed
B. will have changed
C. had been changed
(答案→)D. will have been changed
解析:考查时态。句意:我们相信这的一切事情,在你几年后从国外回来时能够全部改变。结合语境可知从句描述的是将来某个时刻完成的动作,用将来完成时态,everything是被改变的对象,故用被动语态,选D。