What should I write?

[blissful]

Hi

1) Alan was kept after school because he pulled the pigtails of the girls sitting in front of him.
2) Alan was kept after school because he had pulled the pigtails of the girls sitting in front of him.

Thank you

[5jj]

As I often say with this type of question, both versions are fine. Some people feel that only the past perfect is correct (#2) because the pulling happened before the keeping in, but many native speakers are not too concerned about using the past perfect if the sequence of the actions is clear from the context.

[blissful]

Hi

Your quick response is appreciated.

Sometimes, the past perfect tense is used and sometimes the past tense is being used, so it can be quite confusing for learners of ESL.

The car which crashed into the drain belonged to Tom. (Past tense)
There was some cakes that mum had made herself. (Past perfect)

[bhaisahab]

Hi

Your quick response is appreciated.

Sometimes, the past perfect tense is used and sometimes the past tense is being used, so it can be quite confusing for learners of ESL.

The car which crashed into the drain belonged to Tom. (Past tense)
There were some cakes that mum had made herself. (Past perfect)

.

[blissful]

Hi

Thank you for the correction.

Would it make any difference in meaning if the sentence is revised as such.

There were some cakes that mum made herself. (Past tense)

[5jj]

Would it make any difference in meaning if the sentence is were/was revised as such. like this:

There were some cakes that mum made herself. (Past tense)

As I often say with this type of question, both versions are fine. Some people feel that only the past perfect is correct because the making happened before the existence of the cakes, but many native speakers are not too concerned about using the past perfect if the sequence of the actions is clear from the context.

I seem to have read something like that in another post recently.