Difference between had survived, has survived and survived [duplicate]

A visualization of what we mean in English by the various tenses:

For the sake of presenting the information in another way:

I eat

habitually; in general.

• “I eat venison occasionally.”

as a command

• “Now, we eat!”

I am eating

at this point; at this point, continuously; at a point in the future.

• “I am eating these leftovers. Would you like some?”

• “I am eating lunch with John on Thursday.”

I ate

at a point in the past.

• “I ate squid once.”

• “I ate lunch early today.”

I was eating

at a point in the past, continuously.

• “I was eating my dinner, when the phone rang.”

I have eaten

at a point in the past; in the past in general.

• “I have eaten many different kinds of sushi.”

I have been eating

up to and including now, continuously. = I was and am eating.

• “I have been eating the bread that's on the counter, not knowing it's mouldy.”

I had eaten

before a point in the past.

• “I had eaten barbecue before, but this steak was better than any I'd ever tasted.”

I had been eating

up to and including a point in the past, continuously.

• “I had been eating breakfast in bed, till I started seeing ants in my room.”

• “I had already been eating for fifteen minutes by the time she showed up.”

I will eat

at a point in the future; in the future in general.

• “I will eat an apple a day from now on.”

• “I will eat dinner with you tomorrow if you want.”

I will be eating

up to and including a point in the future, continuously.

• “I will be eating only a little bit of this cake. You can have the rest.”

I will have eaten

before a point in the future.

• “I will have eaten by the time you get out of work, so we can't eat together.”

I will have been eating

up to and including a point in the future, continuously.

• “I will have been eating a vegetarian diet for twenty years next month.”

My guess is that you read a table something like this:

• Present Simple (I eat)
  • habitually; in general.
  • as a command
• Present Continuous (I am eating
  • at this point
  • at this point, continuously
  • at a point in the future.
• Past Simple (I ate)
  • at a point in the past.
• Past Continuous (I was eating)
  • at a point in the past continuously
• etc...

and found it confusing. Your first instinct (and it's a good one!) was to draw a diagram to make sense of it. But the diagram is just as confusing as the table.

The problem is that our brains just don't work that way. If you ask a typical native speaker to list all the situations where he uses a particular tense, mood & aspect, he'll find it impossible. But if you show him a sentence and ask him to choose the correct tense, mood & aspect, he'll have no trouble. In other words, our mental table of tenses and moods looks more like this:

• habitually, generally
  • I eat cheese.
• habitually, in the past
  • I ate cheese.
  • I would eat cheese.
• making a request
  • Please eat cheese.
  • Could you eat cheese?
  • Would you mind eating cheese?
  • I was wondering whether you would eat some cheese?
• imaginary situation in the future
  • If I eat cheese, I will have cheese in my belly.
• imaginary situations in the past
  • I wish I had eaten cheese.
• etc.

So if you want to make a diagram that is useful to learners of English, you need to take the same approach. That's a tall order! I don't even know that it's possible. I'd love to know about any past attempts.

One strange property of the perfect tense is that it refers to two times: the time in the past when the action was performed, and the time indicated by the auxiliary verb (to have). Depending upon usage, a sentence using the perfect tense can be more about the present (or the time of the auxiliary verb) than it is about the past:

A: Are you hungry?
B: I have eaten.

B implies he is not hungry because he is in the present condition of having eaten recently. This usage provides a way of talking about a current condition because of recent action.

A: Do you have homework?
B: I have graduated!

B implies he is now in the condition of never having homework because he graduated from school. The emphasis is on the present.

A: What did you do when you ran out of gas?
B: I had been a Boy Scout in my youth, so I was prepared and 
   had a small tank of gas in my trunk.

Although B might be foolish for keeping containers of flammable liquids in the tight confines of his trunk, his Boy Scout readiness existed at the time he ran out of gas.

Humans exist in a flux of ever-changing conditions often resulting from recent actions, and the perfect tense gives us an easy way to talk about them.

Your past perfect tense starts in the infinite past for any action, but it doesn't have to happen so. I include an illustration for the verb see in the past perfect from the following text, written around 2010, which is about a movie that was shelved in 1981, kept for two decades, but finally released around 2002. So, instead of two reference points on the timeline, there can be three.

• The story behind Ladies and Gentleman, The Fabulous Stains is a messy and complicated one. It was riddled with production problems, an editing process that took over a year to complete, and after all was said and done, Paramount Studios decided to shelf the film for over 20 years. … Adler also took over a year to edit the film after shooting wrapped up, allegedly changing the ending several times. Once Ladies and Gentleman, The Fabulous Stains was completed, it was previewed at a few test screenings and the response was so poor that Paramount decided not to release it at all. Many of the cast and crew hadn’t even seen the film in its entirety after it was completed.

------------------------1981=========2002------NOW------------------------

Extra reference points can be included for some other tenses, but I leave that to the readers.