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Present Perfect
We use the Present Perfect to say an action happened at an unspecified time before now. The exact time is not important. You cannot use the Present Perfect with specific timeexpressions such as: yesterday, one year ago, last week, when I was a child, when I lived in Japan, at that moment, that day, one day, etc. We can use the Present Perfect with unspecific expressions such as:ever, never, once, many times, several times, before, so far, already, yet, etc.
Structure
Structure (noun+has have + past participle+complement)
Examples:
* You have seen that movie manytimes.
* Have you seen that movie many times?
* You have not seen that movie many times.
Uses of present Perfect
Experience
You can use the Present Perfect to describeyour experience. It is like saying, "I have the experience of..." You can also use this tense to say that you have never had a certain experience. The Present Perfect is NOT used to describe a specificevent.
Examples:
I have been to France.
I think I have seen that movie before.
Change Over Time
We often use the Present Perfect to talk about change that has happened over a period of timeExamples:
 You have grown since the last time I saw you.
 The government has become more interested in arts education.
Accomplishments
We often use the Present Perfect to list theaccomplishments of individuals and humanity. You cannot mention a specific time.
Examples:
* Man has walked on the Moon.
* Our son has learned how to read.
An Uncompleted Action You Are Expecting
Weoften use the Present Perfect to say that an action which we expected has not happened. Using the Present Perfect suggests that we are still waiting for the action to happen.
Examples:
* James hasnot finished his homework yet.
* Susan hasn't mastered Japanese, but she can communicate.
Multiple Actions at Different Times
We also use the Present Perfect to talk about several different...