现在完成时：have/has done
如:
Have I been there before?
进行时态中的be 此时，be可以与主要动词的现在分词一起，构成各种进行时态。如：
He is reading in the library now.（现在进行时）
She wasswimming in the river this time yesterday.（过去进行时）
They will be arriving in Beijing tomorrow.（将来进行时）
We have been learning English for ten years.（现在完成进行时）
1、be+doing：构成进行时态，有现在和过去两种进行时态。
例句：
The girls is reading and copying the new words now.
Young Tom was always asking questions and trying out new ideas.
2、be+done：构成被动语态(主语是动作的承受者，done必须是及物动词)。
例句：
Tea is grown in my hometown.(一般现在时的被动语态)
This building was built three years ago.(一般过去时的被动语态)
Our classroom has been cleaned and tidied already.(现在完成时的被动语态)
How could this kind of cakes be made in your home?(含情态动词的被动语态)
That is a day never to be forgotten.(动词不定式的被动语态)
3、be+going to do，表示"打算或将要做某事"，be有现在和过去两种形式。
例句：
We are going to plant trees in the park.
I didn't know if she was going to come here.
4、be+to do，表示"按计划安排将要做某事"。
例句：
The new shop is not to be opened till next Monday.
One night an angel came to Mary and told her that she was to have this special boy.
现在完成时的谓语是have + 过去分词，have是助动词，过去分词是主要谓语动词，所以如果动词是be，用be的过去分词形式，即have+been就可以了。
