1) In the middle of the action (in the past)

I was working in Paris when I met my wife

I was waiting for you for two hours yesterday!

Past Perfect

when action has happened (finished) before another action/event in the past

Same as связка of Present -> Past S in the present, there is a pair Past S -> Past Perfect in the past

I cannot believe she ate my sandwich! (Present -> Past S)

I could not believe she had eaten my sandwich! (Past -> Past Perfect)

Past Perfect Continuos

for a long action that had finished before other action/event in the past

They had been playing for half an hour [yesterday] when a terrible storm began

She had been helping them for a couple of hours when the accident happened. ("when" is not necessary)

with words

before after

+ Pr Perf vs Past Simple

! Если нет четкого указания времени - Present Perfect (в том числе "since", "for". Если есть - возможен Past Simple, см ниже)

Becoming a millionaire might have changed him, but his family have helped him to keep his feet on the ground.

If can add "during my lifetime" - use Present Perfect

I have not read his biography (during my lifetime)

I have done smth several times (because the period is "during my life", which has not finished yet)

He have won an Oscar ("during his lifetime")

finished periods of time- Past Simple. We do NOT use Present Perfect with them:

ago, once, during

an hour ago, yesterday, last week, in 2001

They expanded their retail operations significantly during the 1980s. (bc this period has ended)

date or story telling - Past Simple

Once I started going to primary school, the focus of my world changed (not “has changed”, потому что есть указание на время при помощи “once”)

How long have you been in Egypt - если только что/недавно приехал

How long were you in Egypt - not have been, потому что уже приехал

He worked for the police for 17 years (если сейчас уже не работает),

I worked in Paris for months (the period has ended)

Same for "since"

He has been learning English for 5 years (now)

He had been learning English for 5 years (when he was young) (not "was learning" bc of "for")

People had been ignoring the problem for years (before smth happened - in context)

George has bought a new car

George bought a new car after his wife had told him

But: She was telling me that boring story for hours - ? (past cont - because strongly focusing on the the legth of action - if was soooo long and boring)

Switch from Past to Present Perfect (through Present Simple)

Past, past, past (рассказ в прошлом)

Today, Bewley's is(i) Ireland's leading supplier of quality coffees and teas.

It has created a catering service (Switch to present -> now can use Pr Perf)

!

Зависит от контекста. Если контекст про прошлое - используем Past Simple. Если есть связь с настоящим, с контекстом настоящего - Present Perfect

I studied at school in 2005 - указание времени

I have studied at school since 2005 - если недавно закончил (Pr Perf)

He worked for the police for 17 years (если сейчас уже не работает),

I have been studying at school since 2005 - если учишься до сих пор

I was in New York City for four months (also if you imply "last year", "in 2005" etc., if it is in the context). - merely talks about the past event that you were present at that place.  I have been there in New York City in the past (for four months), so I know how do New Yorkers celebrate Christmas. - also emphasize that that event has something to do in the present talk/context.

My friend went to Iran. After he had uploaded photos from his trip, I saw that there is nothing there but sand and desert.

can say: When he uploaded photos, I saw …

+ Past Simple vs Past Perfect

Past Simple

We use Simple Past if we give past events in the order in which they occurred, последовательный sequence of events

I got to the airport and discovered

I got to the airport, then discovered

First I did not know what to write but then I had lots of ideas. (not "had not")

he told me that he came home (Past Simpl in both cases)

First thing we noticed when we entered …

Past Perf

"before", "after", "until", "by the time" in the sentence - MUST use Past Perf

Past-perf before Past Simple

Past Perf until Past Simple

Past-Simple after Past-Perf

By the time / when Past simple (time in the past), Past Perf

he explained that all the stories he had told us were true (before is implicit here)

The blue car crossed the street after the lights had turned red.

Before her sixth birthday, Jane had never been to the zoo.

Jane had read a lot about elephants before she went to the zoo.

After the family had had breakfast, they went to the zoo.

After I had heard the news I could not think about anything else

but: After her visit to the zoo, Jane was exhausted. (object, not a normal verb, + subject + verb)

this policy before 1835 had forced the Irish to import their tea from London.

By the end of the 19th century a tea culture had developed in Ireland.

Now that I had found my notes, I wanted to continue writing my essay.

Often after "because"

Bob did not let us into his room because he had not cleaned it for weeks.

Diane had lost her car keys so she took a cab

Misc

I had almost completed my essay when my computer suddenly crashed and I noticed that I had forgotten to save the document.

Barbara had smoked a lot but during her last stay in the USA she gave it up. (not "smoked")

When we arrived, the party started (party started after we arrived)

When we arrived, the party had started (party started before we arrived)

he has done smth before

he did smth earlier

+ Pr Perf vs Pr Perf Cont

В perfect всегда есть завершенность действия (к моменту времени)

В continuous - всегда есть длительность действия и акцентирование на нем (т.е. это важно, что оно такое долгое)

I've written two letters this morning - уже закончил

I've been writing two letters this morning - Писал и продолжаю писать

+ Future

Present Cont

definite plan for the future, если запланировал что-то с кем-то

We are meeting tomorrow

we are going to the club on Tuesday night - запланировано

arrangement in the future (с кем-то еще), predictions on what you know

Going to

Если запланировал делать что-то один и не уверен до конца, что сделаешь - going to

I’m going to buy some bread

Look at those clouds! It’s going to be rain! (Предсказание будущего основанное на текущих наблюдениях, т.е. более-менее обоснованное предсказание)

Future Continuous

at 9:30 pm, this time tomorrow

I will be working on the report all next week (= during next week)

We can also use ‘may be doing’ instead of ‘will be doing’

Future Perfect is used with

by, until (use in neg sent)

by that time, by tomorrow (by some time in the future).

The film will have finished by midnight (завершенность к будущему моменту времени)

Future simple

timetables

the train leaves tomorrow at 5.

What time does the film begin? (not "at what time" - seems that preposition is omitted in questions)

predictions based on what you know or believe - it will rain tomorrow