B)Model: I am sorry we didn't think about it before
I wish we had thought about it before
1. I am sorry you didn't see this film before.
2. I am sorry i didn't do it for you before.
3.I am sorry they didn't visit this museum.
4.I am sorry i wasn't there before.
5.I am sorry the didn't stage this performance before.

C)Model: If i saw this film i would tell you about it.
If i had seen this film yesterday i would have told you about it.
1.If you chose this room you would watch TV.
2.If you investigated this problem you would answer this question.
3.If he measured the temperature he would explain this phenomenon.
4.If they unified the facts they would prove the problem.
5.If they processed the data they would have the results

BI wish you had seen this film before.I wish I had done it for you before.I wish I had visited this museum.I wish I had been there before.I wish they had staged this performance before.CIf you had chosen this room you would have watched TV.If you had investigated this problem you would have answered this question.If he had measured the temperature he would have explained the phenomenon.If they had unified the facts they would have proved the problem.If they had processed the data they would have had the results.