Teach me English! (Past Perfect)?

Question

I'm a Japanese speaker. Teach me English.

Past tense, Past Perfect, Present Perfect always give me hard time. They are sometimes really confusing.

My English Book says,
｢The criminal has been in prison for 10 years. ｣　is OK
｢The criminal has been in prison for 10 years but　he is free now｣ is not correct.
The criminal's prison life is over. so It should be past tense of WAS for that sentense.

I found this term on the same text book.
He had worked for 30 years until she retired.

Why is Past Perfect used in this term? Because his job is over now. He is no longer working. That's why I think the verb should be (WORKED).

I'd like you to explain those terms.
Thank you in adance.

Answer 1

Has been means that it happened in the past, and is still happening now in the present time (he was in prison 10 years ago and is still there now)

Was in prison, but is out now (he is no longer in prison, the action does not continue on in the present time)

Had worked means that the action happened in the past, but is not happening now (he was working there for 30 years, but he is no longer working there at this time, action is not happening now in the present time)

You will find that people will often use "worked' instead of "had worked" in everyday speech. It is problematic even for native speakers.

Answer 2

Past perfect is used when you are talking about two events, both have already occurred, and you want to indicate that one event happened farther in the past than the other. Past perfect uses "had". For example:

First, I received my diploma. Then I moved away from the university. So, "I had received my diploma when I moved away from the university."

Present perfect is when the action started in the past but is still continuing. Such as, "I have worked as a nurse for 28 years." I began 28 years ago, and I am still working as a nurse -- use the word "has".

If an action is simply over, and not continuing now, and you are not comparing the relative occurrence of two past events, use simple past tense. "I worked last night." No "have" or "had" is used here.

Good luck! It is not easy at first, but you can master this!

Answer 3

Past perfect is used for an action that occured before another past action.

First he worked, then he retired. (I'm assuming your "she" is a typo.)
In fact, in this case and others in which it's clear that one action precedes another (obviously you have to work before you can retire), the simple past is also accepteble (though not AS good). Past perfect is only really necessary when the times of the two events are not otherwise distinguishable.

I ate the cake when he came home.
vs. I had eaten the cake when he came home or I ate the cake when he had come home.
(You can also make the distinction with "before" or "after".)