long have you been in this city?
问题描述：
long have you been in this city?
—How long have you been in this city?
—____C____ twenty years.
A.Before B.After C.For D.Since
求解析和翻译
答
回答是I have been in this city for twenty years.
省略了I have been in this city .
在回答在某地已经呆了多长时间的时候,在时间前都要加for