第1个回答 2014-07-31
现在完成时
1.概念:过去发生或已经完成的动作对现在造成的影响或结果,或从过去已经开始,持续到现在的动作或状态。2.时间状语:yet,already,just,never,ever,so far,by now,since+时间点,for+时间段,recently, lately, in the past few years, etc.
3.基本结构:have/has + done 4.否定形式:have/has + not +done.
5.一般疑问句:have或has。
6.例句:I've written an article. The countryside has changed a lot in the past few years.