Pete didn't wear a coat. He didn't expect it to be cold. Had Pete.......
Had Pete known it was so cold, he would have worn a coat.
You didn't tell me it was a casual dinner. I'm wearing my dinner jacket. Had you told me.......
Had you told me it was a casual dinner, I would have worn something else.
Darius didn't phone. Kate was angry. Had...
Had Darius phoned, Kate wouldn't have been so angry.
You may need help filling out the application. Give me a call if you do. Should.......
Should you need help filling out the application, give me a call.
There was a train strike. We were late. Had _______ the fact that there was a train strike, _______ on time.
Had it not been for the fact that there was a train strike, we would have been on time.