I was reading through C1C2 Destination when I found this strange sentence.
Paul told me that Dawn hadn't been particularly hardworking when she was at university.
I am wondering why it is she was at but not she had been at, as it is referring to the past. Please help me with this question.
She had been is the past perfect tense. She was is the past tense, sometimes called past simple. Both of these tenses refer to the past, so when you say it should be had been because "it is referring to the past", that's not correct. A better way to understand the past perfect tense is that it refers to the relative past. In other words, the perfect past tense describes an action that happens before some other action.
It's also important to understand that the choice of tense is often not a 'right or wrong' choice. It's quite possible for past and perfect past tenses to be correct, but they will mean different things or have a different emphasis.
So in your example, we could use different wordings, all correct:
Paul told me that Dawn wasn't particularly hardworking when she was at university. Here we have two verbs, both in the simple past tense. Paul is looking back to Dawn's time at university, so past perfect could have been used. But that's not necessary because we know from the context that Paul is describing an even earlier time in the past.
Paul told me that Dawn hadn't been particularly hardworking when she was at university. Here we have Paul speaking in the past ('told me') about an even earlier time when Dawn was at university. So the relationship between these events is the same as before, but here the writer wants to emphasise that time difference by using the past perfect. He only uses one past perfect tense because that's enough. Dawn's time at university and her time of not working are the same time period, so the first past perfect covers them both.
Paul told me that Dawn hadn't been particularly hardworking when she had been at university. This is the proposed sentence in the OP, and it's not wrong, but my view is that it's not the most natural. Remember that the past perfect tense points to relative time. So the reader is invited to look back and ask, what is the other event that this event comes before? Dawn "hadn't been hardworking": this obviously happens before Paul "told me". But what about "had been at university"? Is that before Paul telling me, or is it even further back before Dawn's period of non-working? In this case the answer is reasonably clear cut, but the point is that the more we pile up past perfect verbs, the harder it can be to keep track of the order of events.
