现在完成时态
⑴由have/ has ＋ 过去分词
⑵表示过去发生或已经完成的某一动作对现在造成的影响或结果
常与already, just , yet , ever, never 连用
Have you finished your work yet？你完成了你的工作了吗？
Yes, I have. I have just finished it. 是的。我刚刚完成了。
I have already finished it . 我已经完成了。
Have you ever been to China? 你曾经去过中国吗？
No, I have never been there. 没有，我从来也没有去过。