1 The teacher would be pleased if the pupils greeted him.
2 I will certainly do it if it is possible.
3 If you did the job carefully, you would get better results.
4 I would be terribly sorry if he broke the vase.
5 They will be foolish if they don’t take this opportunity.
6 I would be scared if a thief walked in here. Я испугалась бы, если бы сюда вошёл вор.
7 If she were older, she would have more sense.
8 What would you do if your car was stolen?
8 What would you do if your car was/were stolen? (в придаточной части (условии) условных предложений допустимо использовать were вместо was)