Present Perfect Tense

We use the Present Perfect to say that an action happened at an unspecified time before now. The exact time is not important. You cannot use the Present Perfect with specific time expressions 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. 

Examples:

Formula:

(+) S + have/has + V3

(-)  S + have/sas Not + V3

(?) Have/has + S + V3 + ?

Here are some examples of the present perfect tense:

subject	auxiliary verb		main verb
+	I	have		seen	ET.
+	You	have		eaten	mine.
-	She	has	not	been	to Rome.
-	We	have	not	played	football.
?	Have	you		finished?
?	Have	they		done	it?

When we use the present perfect tense in speaking, we usually contract the subject and auxiliary verb. We also sometimes do this when we write.

I have	I’ve
You have	You’ve
He has She has It has John has The car has	He’s She’s It’s John’s The car’s
We have	We’ve
They have	They’ve
	They’ve

Examples:

• You have seen that movie many times.
• Have you seen that movie many times?
• You have not seen that movie many times.