E. Đảo ngữ của câu điều kiện
1. Điều kiện loại I
• Nếu trong câu có “should” ở mệnh đề if, thì đảo “should” lên đầu câu
If he should ring , I will tell him the news. → Should he ring, I will tell him the news.
• Nếu trong câu không có “should”, chúng ta phải mượn “should”
If he has free time, he’ll play tennis. → Should he have free time, he’ll play tennis. If she comes early, we’ll start. → Should she come early, we’ll start.
2. Điệu kiện loại II
• Nếu trong câu có động từ “were”, thì đảo “were” lên đầu.
If I were a bird, I would fly. → Were I a bird, I would fly. They would answer me if they were here. → Were they here, they would answer me.
• Nếu trong câu không có động từ “were” thì mượn “were’ và dùng “ to V”
If I learnt Russian, I would read a Russian book. → Were I to learn Russian, I would read a Russian book. If they lived in Australia now, they would go swimming. → Were they to live in Australia now, they would go swimming.
3. Điều kiện loại III • Đảo trợ động từ của thì quá khứ hoàn thành.
If it had rained yesterday, we would have stayed at home. → Had it rained yesterday, we would have stayed at home. If he had trained hard, he would have won the match. → Had he trained hard, he would have won the match.
Chú ý: ở dạng phủ định, “not” được đặt sau chủ ngữ:
Had it not been so late, we would have called you.