2. Read each pair of sentences. Then express a contrary situation using a) a sentence with an if clause and b) a sentence with had. Follow the examples.
Examples:
I didn’t know you were there. I didn’t telephone.
a. If I had known you were there, I would have telephoned.
b. Had I known you were there, I would have telephoned.

1.I didn’t hear you. I didn’t answer.
　a.
 
　b.
 
2. It was cold. I didn’t open the window.
　a.
 
　b.
 
3. We weren’t late. We didn’t hurry.
　a.
 
　b.
 
4. You didn’t use a typewriter. They couldn’t read your letters.
　a.
 
　b.
 
5. The car stopped. It didn’t hit me.
　a.
 
　b.