1. People don't realise how important it is to conserve energy, so they do nothing about it.
=> If
2. If he doesn't change his way, he'll end up in prison.
=> Unless
3. Barbara playssquash better than Mike.
=> Mike
4. Nobody told me that George was ill.
=> I
5. Tim regrets missing the flim on TV last night.
=> Tim wishes
1. People don't realise how important it is to conserve energy, so they do nothing about it.
=> If people realized how important it is to conserve energy, they would/ might do something about it.
2. If he doesn't change his way, he'll end up in prison.
=> Unless he change his way, he will end up in prison
3. Barbara plays squash better than Mike.
=> Mike doesn't play squash as good as Barbara
4. Nobody told me that George was ill.
=> I wasn't told that George was ill
5. Tim regrets missing the flim on TV last night.
=> Tim wishes Tim hadn't missed the flim on TV last night.