很多人对这一点很难理解，其实如果给一个完整的环境来看就非常简单。比如你说的句子，如果是有人对你说Please open the door.那么你可以回答 I have opened the door.这句话的隐含意思就是说The door is open now.（这就是你说的句子中的动作的结果）再比如，有人邀请你Would you like to have an apple, please?你回答：I have had one.就等于说Thank you, but I don't want any more.（这也是结果）慢慢体会...
