Learn English – Past simple vs. past perfect

grammarpast-perfectpast-tensetenses

Here is an exercise from Intermediate Language Practice by Michael Vince:
(Please note that I have replaced all the blanks in the exercise with the answers given in the answer key.)

Put each verb given into the past simple, past continuous or past
perfect. More than one answer may be possible.

(A picture showing a man being seized by a police officer)

The police suspected that Brian (1) had broken the window at his
house because he (2) wanted to make them think that a burglar (3)
had stolen his valuable stamp collection. They (4) thought that Brian (5) had done this because he (6) needed the money. However,
they (7) didn't know that Brian (8) had flown to Brazil the week
before, and (9) had been/was abroad when the burglary (10) took
place/had taken place
.

My questions are:

  1. At (2) and (6), is it possible to use the past perfect instead of the past simple? As I understand it, the past simple is used here to indicate that Brian's "wanting to fool the police" and "needing the money" were still in his mind at the time he was being seized by the police. If I used the past perfect instead in order to talk about his state of mind at the time the burglary took place, would the sentences sound right?
  2. At (9) and (10) why is it possible to use the past simple when "his being abroad" and "the burglary" had both taken place before he was captured by the police? Which of the following sentences are acceptable? Which one is the best?

    a. However, they didn't know that Brian had flown to Brazil the week
    before, and had been abroad when the burglary took place.

    b. However, they didn't know that Brian had flown to Brazil the week
    before, and had been abroad when the burglary had taken place.

    c. However, they didn't know that Brian had flown to Brazil the week
    before, and was abroad when the burglary had taken place.

    d. However, they didn't know that Brian had flown to Brazil the week
    before, and was abroad when the burglary took place.

Best Answer

A bigger problem with all forms of 2 is that the second comma shouldn't be there.

In "However, they didn't know that Brian had flown to Brazil the week before, and had been abroad when the burglary took place." the comma breaks up the list of things "they" didn't know, which was one intended purpose of the "and". The "and" now makes the "had been abroad..." refer to the "they" instead of "Brian".

The "was abroad when the robbery took place" is a direct consequence of Brian's having gone to Brazil, and is the other purpose of the "and" (i.e. "and therefore").

A sentence shouldn't start with "however", either, so a better construction would be:

"They didn't know, however, that Brian had flown to Brazil the week before and had therefore been abroad when the robbery took place."