Давайте разберём каждое предложение и преобразуем его в соответствующее время.
What a letter to her parents yesterday.
- Правильное предложение: "What a letter she wrote to her parents yesterday." (Past Simple)
Pete asked him to do it.
- Правильное предложение: "Pete asked him to do it." (Это также в Past Simple, так как форма уже верная).
At noon Mike in the library.
- Правильное предложение: "At noon Mike was studying in the library." (Past Continuous, добавлено "was studying").
Jack told us that he still.
- Правильное предложение: "Jack told us that he had still been working." (Past Perfect Continuous, добавлено "had been working").
Nancy
- Правильное предложение: "Nancy had written an email when she was interrupted." (Past Perfect, добавлено "had written").
Who never
- Правильное предложение: "Who had never seen the postcards?" (Past Perfect, добавлено "had never seen").
when I entered the room?
- Правильное предложение: "What was she writing when I entered the room?" (Past Continuous, добавлено "was writing").
I didn't know who
- Правильное предложение: "I didn't know who had written this note the day before yesterday." (Past Perfect, "had written").
Paul you
- Правильное предложение: "Paul had been writing her essay for an hour when the bell rang." (Past Perfect Continuous, добавлено "had been writing").
the paper by midnight?
- Правильное предложение: "Did you finish the paper by midnight?" (Past Simple, добавлено "finish").
the report.
- Правильное предложение: "Had she submitted the report?" (Past Perfect, добавлено "submitted").
a lot when he was at school.
- Правильное предложение: "He had studied a lot when he was at school." (Past Perfect, добавлено "had studied").
an e-mail when she was interrupted.
- Правильное предложение: "She had been writing an e-mail when she was interrupted." (Past Perfect Continuous, добавлено "had been writing").
Теперь давайте перейдём к теговым вопросам:
John bought a history book, didn't he?
- Правильно.
Mrs Smith had brought some fruit and vegetables by noon, hadn't she?
- Правильно.
The second lesson didn't last long, did it?
- Правильно.
The girl was singing a nice song when we entered, wasn't she?
- Правильно.
The car had stopped before the policeman saw it, hadn't it?
- Правильно.
Paul had been working with Ann for a year before she left, hadn't he?
- Правильно.
Three guests hadn't arrived by 7 p.m., had they?
- Правильно.
The sisters were looking for the keys when their mother came, weren't they?
- Правильно.
The English teacher gave a lot of homework, didn't he?
- Правильно.
Thousands of people were present at the match, weren't there?
- Правильно.
Nancy had cooked dinner by 3 p.m., hadn't she?
- Правильно.
Все предложения и вопросы составлены правильно и соответствуют требуемым временам. Если у вас есть другие вопросы или нужно что-то объяснить более подробно, пожалуйста, дайте знать!