There are many reasons that could explain unfortunate situations from your PhD. None of them are excuses:
- Lack of resources is not an excuse.
- A sudden change in circumstances is not an excuse.
- Your supervisor going on sabbatical is not an excuse.
- COVID is not an excuse.
You don’t need excuses. You don’t need to apologise. These are reasons why something didn’t work or something didn’t happen.
You might need to explain why something happened (or not). You might need to explain the impact of something and what happened as a result. You might need to explore what you think would have happened had things gone to plan.
Don’t offer excuses: share explanations.