ところを
(Tokoro o)
(although) at / while / in the middle of (polite apology).
Connection rules
- +V plain / i-adj + ところを; na-adj + な + ところを; noun + の + ところを.
- +Polite apology for interrupting — formal business register.
- +Common fixed phrase: お忙しいところを (apologizing for taking busy time).
Examples
1.
お忙しいところを、ありがとうございます。

Oisogashii tokoro o, arigatou gozai masu.
Thank you for your time despite being busy.
「(although) at / while / in the middle of (polite apology)」
2.
お休みのところをすみません。

O yasumi no tokoro o sumi mase n.
I'm sorry to disturb your rest.
「(although) at / while / in the middle of (polite apology)」
Practice
I am very sorry to trouble you while you are on vacation.
___、お邪魔して大変申し訳ございません。
Romaji also accepted