英语基础语法-12完成进行时
完成进行时（Perfect Progressive Tense）：描述一个动作在过去周期性重复，并且持续到现在，并且或者在将来也继续。
如果单独看完成时态，它有一个基本的含义即表示到某个时间为止，该动作已经完成，所以它称作“完成时”。但是，在完成进行时里面，一般情况下，它并不表示动作的“完成”，而是表示长时间的持续状态。也就是说，完成进行时侧重于“进行”。
如果单独看进行时，它表示某个时间内动作正在进行，而完成进行时则侧重于长时间的持续状态。如果简单地说，完成进行时实际上是一种强调动作持续发生的进行时，并且含有动作反复进行的意思。
以上就是完成时、进行时、完成进行时之间的联系和区别。
现在完成进行时（present perfect progressive tense）
描述一个持续的动作在过去开始发生，在过去的某个时点结束；这个动作和现在是有某种联系的。
使用have/has + been + ing表现形式。
- It has been raining, and the street is still wet.
- I have been running, and I am still tired.
- She has been practicing the piano, and she is much better now.
强调动作在一段时间内反复发生。
We have been seeing quite a lot of each other recently.
最近我们常常见面。
强调动作在长时间内持续不断。
All these years they have been contributing articles to our magazine.
这些年来，他们一直为我们杂志写稿。
How long have you been watching TV?
你看了多久电视了？
过去完成进行时（past perfect progressive tense）
描述一个在过去发生的持续的动作，并且在过去的另一个动作之前已经结束了。
使用had + been + ing表现形式
- It had been raining, and the street was still wet.
- I had been running, and I was still tired.
- She had been practicing the piano, and she had gotten much better.
将来完成进行时（future perfect progressive tense）
描述一个持续的动作会在将来的某个时刻结束。
使用will + have + been + ing表现形式
- By tonight, it will have been raining several hours, and the street will be very wet.
- By next summer, I will have been running for almost a year, and I will be fit and healthy.
- By the time of the concert, she will have been practicing the piano for several months, and she will be much better.
练习
找出不正确的句子。
- I have been sleeping all day today.
- They will have been walking for almost an hour by the time they arrive at their destination.
- She have been eating a lot recently.
答案：
3) have -> has