2.条件句中虚拟语气的倒装； 条件从句中含有should，were， had 三个助动词可将其放在句首，并把if省略。 If I were you, I would give it up. Were I you, I would give it up. If I had had time, I would have run round that lake again. Had I had time, I would have run round that lake again. If there should be a flood, what should we do? Should there be a flood, what should we do?