1.“一般过去时”所关心的是过去之事,与现在无联系，常带有表示过去某个时间的状语；现在完成时所关心的是过去发生的事，与现在有影响和联系，对现在产生某种结果；现在完成时强调过去与现在的联系。
①Ａ: I ________(lose) my pen. Can you lend me yours?
Ｂ: Why don't you buy one?
Ａ:.It _______(fall) into the river only a moment ago when I washed my hands. Now I've got to fill in a form with a pen.
