仮定法未来
If S should do ... / If S were to do ...
(Should S do ... / Were S to do ... のように倒置しても意味は同じ)
「(あり得ないと思うけど今後)ひょっとして~したら」
● If he should come, I would let you know at once.
Should he come, I would let you know at once.
もし万一彼が来たら、あなたにすぐにお知らせします。
● If Japan were to win the World Cup, I would give you one million yen.
日本がワールドカップで優勝するようなことがあったら、お前に100万円やるよ。