2016-06-23
xredued04
4.在表示“最近几世纪/ 年/ 月以来……”时间状语中，谓语动词用现在完成时。
in the past few years/months/weeks/days;over the past few years; during the last three months; for the last few centuries, through centuries; throughout history 等
5.表示“第几次做某事，”或在 “It is the best (worst, most interesting ) +名词 +that” 后面跟现在完成时。
例：This is my first time that I have visited China.
This is the most interesting film I have ever seen.
That is the only book that he has written.
6. have / has been to + 地点 意为“曾去过某地”，暗含目前已不在该地，仅表示当事人的一种经历而已。
have / has gone to + 地点 “到某地去了”，暗含“已离开原地去了某地”之意，但是否到达了某地尚不确定。
如：He has gone to Shanghai. 他去了上海。
He has been to Shanghai. 他去过了上海。