Explanation:

Dear Mr and Mrs Williams,

I hope you are doing great. It is a shame that we do not KNOW each other very well and I would like to apologise for that. I am writing this letter in response to your complaint letter that you sent me YESTERDAY about the noise from my flat. I sincerely apologise for the INCONVENIENCE and humbly ask for your forgiveness.

With the concern about home safety, my wife and I decided to install a few smoke detectors in our flat, especially after we saw a devastating fire in our neighbourhood lately. We bought the devices from an online store and started to install and test the gadgets last Sunday. To ensure that the sound of the fire alarm is loud ENOUGH and everyone in the house would notice it, we tested the devices for about 30 minutes. Although the testing TOOK place at midday last Sunday, my wife and I are terribly sorry that your child’s nap was interrupted.

I really regret the event and request your forgiveness. Please accept this box of chocolate as a token of my deepest regret for the inconvenience. We will be more careful next time.

Yours sincerely,

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