Напишите кратко о правиле past perfect

современно время,которое обозначает действие,уже закончившегося до определённого времени в Данный момент может быть указан точно с предлогом "by" или может быть выражен другим действием.

1)1. cooked 2. was cooking 3. was cooking 4. i was not (=wasn't) reading … 5. i was not (=wasn't) reading … 6. what was he doing when i came in? 7. what was he doing … ? 8. watered 9. was watering 10. what was pete doing … ? 2)1. came; was having 2. returned; was listening 3. entered; was drawing 4. came in; was doing 5. was airing; caught 6. met; was going 7. was washing; knocked 8. were dancing; came 9. was washing; broke 10. what were they doing when you saw them?

Iattend secondary school №78. i started school in 2009 at the age of 7 and now i’m a pupil of the 6th form. my first teacher was tatiana orlova. she was the teacher of math. she taught us to write, to read and to count. she was very kind and patient. i really liked my first teacher.. we often went for walks and excursions. we played together and became good friends with our classmates.at the age of 11 i went to the secondary school. our school has two buildings. elementary school is located in the red building, and secondary school   in the white building.  it is very good that the younger children have their own building.when we went to the secondary school we began to study a lot of new subjects such as history, geography, physics, chemistry. most of all i like literature, history, english.i like our school.i have very many good friends here .we spend a lot of time together, help each other. our school-life is very interesting. we    visited museums and theatres.we rode the train to st. petersburg and moscow.i like to dance, and i think that our school should be spending more dance parties at school.i think that i’m really happy at school.