与将来的事实可能相反

If it should rain tomorrow, I would stay at home.要是万一明天下雨，我就呆在家里不出去。（事实上现在天气很好，明天下雨的可能性应该不大，不过也说不准。）/If I should see her next Monday, I would tell her about it.如果下周一我能见到她的话我就把这件事告诉她。