for one thing
US /fɔːr wʌn θɪŋ/
UK /fɔːr wʌn θɪŋ/

1.
ten eerste, om te beginnen
used to introduce one reason, among others, for something
:
•
I can't go out tonight; for one thing, I have to study.
Ik kan vanavond niet uit; ten eerste, ik moet studeren.
•
Why didn't you tell me? Well, for one thing, you were busy.
Waarom heb je het me niet verteld? Nou, ten eerste, je was druk.