in the first place
US /ɪn ðə fɜːrst pleɪs/
UK /ɪn ðə fɜːrst pleɪs/

1.
そもそも, まず第一に
used to refer to the beginning of a situation or to the original reason for something
:
•
Why did you agree to go in the first place?
そもそもなぜ行くことに同意したのですか?
•
I never wanted to come here in the first place.
そもそもここには来たくなかった。
2.
まず第一に, 第一に
used to list the first point in a series of reasons or arguments
:
•
In the first place, we don't have enough money. Secondly, we don't have enough time.
まず第一に、私たちには十分なお金がありません。次に、十分な時間がありません。
•
There are several reasons why I can't help you. In the first place, I'm too busy.
あなたを助けられない理由はいくつかあります。まず第一に、私は忙しすぎます。