现在完成时是“助动词have(has)+过去分词（done)”构成。
现在完成时的用法：
（1）表示过去发生或已经完成的动作对现在造成的影响或结果。例：__Have you had your lunch yet?
__Yes,I have.I have just had it.(我小现在不饿了。）或I have already posted the photos.
(2)某些动词的现在完成时可表示过去某一时间开始并一直持续到现在（包括“现在”在内）的动作或状态，可以和表示延续的时间状语连用。表示持续动作或状态的动词多是延续性动词。例：I have not seen her these days.或：They have lived here sine 1999.
(3)现在完成时可以和already,ever,just,never,yet等状语连用。例：Have you ever eaten chiken and fish？或：I have never been to that shop before.
（4）have（has)been和have(has)gone的区别：have(has)been表示“曾经去过某地”，have(has)gone表示“已经去某地了”。例：Where has she been?（她刚刚到哪儿去了？即她已经回来了。）或：Where has she gone?(她到哪儿去了？即她不在这里。）
现在完成时的用法：
（1）表示过去发生或已经完成的动作对现在造成的影响或结果。例：__Have you had your lunch yet?
__Yes,I have.I have just had it.(我小现在不饿了。）或I have already posted the photos.
(2)某些动词的现在完成时可表示过去某一时间开始并一直持续到现在（包括“现在”在内）的动作或状态，可以和表示延续的时间状语连用。表示持续动作或状态的动词多是延续性动词。例：I have not seen her these days.或：They have lived here sine 1999.
(3)现在完成时可以和already,ever,just,never,yet等状语连用。例：Have you ever eaten chiken and fish？或：I have never been to that shop before.
（4）have（has)been和have(has)gone的区别：have(has)been表示“曾经去过某地”，have(has)gone表示“已经去某地了”。例：Where has she been?（她刚刚到哪儿去了？即她已经回来了。）或：Where has she gone?(她到哪儿去了？即她不在这里。）
