现在完成时：动名型have+过去分词，系表型have been+表语。现在完成时，表示曾经有过的经验，表示过去某种行为的结果对现在有直接的影响，表示某经历的时间长度。

过去完成时结构：主语+had+done+sth。有before+、by+过去的时间点的时间状语时用过去完成时态。

完成时态的句子 ：

I had writed half of book by the end of last week. 在上周之前，我就已经写了半本书了。

I had finished my homework by the end of hoilday. 我在假期结束之前就做完了作业。

I have finished my homework.我已经做完作业了 。

I have had breakfast.我已经吃过早饭了。