1、一个动作发生在过去 并持续到现在并可能继续持续下去.
I have lived here since i was born
2、一个动作发生在过去对现在造成影响
Eddie has just eaten Hobo's food
3、到现在为止一个动作发生过多少次
I have already read this book many times
出现 already yet ever just never since recently for 用现在完成时 for+一段时间（延续性动词）
1、一个动作发生在过去 并持续到现在并可能继续持续下去.
I have lived here since i was born
2、一个动作发生在过去对现在造成影响
Eddie has just eaten Hobo's food
3、到现在为止一个动作发生过多少次
I have already read this book many times
出现 already yet ever just never since recently for 用现在完成时 for+一段时间（延续性动词）