There are two main uses of the present perfect tense in English. We can use the present perfect:

 

• For actions at unspecified point in time in the past.

• For actions over a duration of time from the past up until now.

 

Usage 1:

 

ExFor actions at unspecified point in time in the past.

 

Positive: subject + have/has + verb 3

Example:  I've written a book.

 

Negative: subject + have/has + not + verb 3

Example:  I haven't written a book.

 

Question: have/has + subject + verb 3

Example:  Have you written a book?

 

Usage 2:

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For actions over a duration of time from the past up until now.

 

Positive: subject + have/has + verb 3

Example:  They've been here for a long time.

 

Negative: subject + have/has + not + verb 3

Example:  They haven't been here for a long time.

 

Question: have/has + subject + verb 3

Example:  Have they been here for a long time?ample: Have you written ...