Apologies, excuses, and thanks

Apologies (= saying sorry)

We can apologise (= say sorry) in different ways in different situations:

Note: In formal situations (especially in writing), we often use apologise and apology:
I must apologise for (being late). I would like to apologise for (the delay. Unfortunately, …)
Please accept our apologies for the mistakes in your order. We tried to …

Excuses and promises

If the situation is quite important we usually add an explanation or excuse after the apology. An excuse is the reason for the apology, which may or may not be true. (If it is not true, it should still be a reason that people will believe.) Here are some common excuses:

I’m sorry I’m late but I was delayed/held up at the airport.
I’m sorry I’m late, but my train was cancelled. (= the train was timetabled but did not run)

Note: To be/get delayed or be/get held up (infml) both mean to be late because of a problem that is out of your control.

If you are responsible for a problem, you can offer or promise to do something about it.
I’m sorry about the mess in here. I’ll clear it up. (= I’ll tidy it up)
I’m sorry about the confusion, but I’ll sort it out. (= I will solve the problems)

Reassuring people

When people apologise to us, it is very common to say something to reassure them (= tell them that ‘everything is OK’), and that we are not angry. These are all common expressions. Note that we often use two of them to emphasise the fact that ‘it’s OK’.

A: I’m sorry I’m late. B: That’s OK. Don’t worry, or Never mind. It doesn’t matter, or

That’s OK. No problem.

Thanks

These are the most common ways of thanking people in everyday situations:
A: Here’s your pen. B: Oh, thank you / thanks (very much).
A: I’ll answer that. B: Oh, thanks a lot (infml).
A: I’ll post those letters for you. B: Oh, thank you. That’s very kind of you.
If you go to someone’s house for dinner, or stay with people in an English-speaking country, you will need to thank them for their hospitality (= when people are kind and friendly towards their guests). You could say something like this:

Thank you very much for inviting me. It’s been a lovely evening.
Thank you very much for everything. You’ve been very kind.