It's about [high] time (that) we started working on the project.
その計画にとりかかる時期が来ている（◆that節中の動詞は過去形がふつう）
It's against my better judgment, but ....
不本意ながら…
It's all because of you.
きみのせいだ
It's all in the mind.
みんな気のせいだ
It's all in the past.
((略式))すべて昔のことだ（忘れよう）
It's all on expenses.
それはすべて会社持ちだ
It's all one to me.
私にはどちらでも同じことです
It's all the same to me whether you pass the exam or not.
あなたが試験に合格しようがしまいが私にとっては同じことだ
It's an ill wind that blows nobody good.
((諺))だれにも利益をもたらさない風は吹かないもの；甲の損は乙の得
It's been a long time since I've seen you.
ずいぶん久しぶりだね
