That would be the worst possible result.
それが考えられる最悪の結果だろう
That would just (about) finish me off.
そんなことをすれば身が持たない
That would never do.
((略式))それでは全然だめだ,そうなるとまったくまずい
That'll do me fine, thanks.
それでいいよ,ありがとう
That'll learn you.
これでこりるだろう
That'll teach you.
これでやっとわかったか,何回も言ったじゃないか
That's (past [ancient]) history.
それはもう昔の話だ
That's (a bit) rich(, coming from you)!
(君に言われるなんて)お笑い草だ
That's (just) the (very) thing I was looking for.
ちょうど[まさしく]探していたものだ
That's a big but.
それは大きな条件[問題点]だ