5 sentences :)

1) If he had known french been better at French, he would have read french's French books in the original. But he didn't pay attetion to the languege that time. But he wasn't interested in the language at the time. 
2) I would have gone here immidently there immediately (or 'I would have left immediately), if I had known what there are had happened. Why did you talk me nothing? Why didn't you say anything to me? You just suggested me that I wait.
3) If I were not so busy, I would see my relatives off to the airoport have seen my relatively off at the airport, or 'I would be seeing my relatively off at the airport'. I had no time last week / or 'I've had no time the last few weeks'. Depending on whether you mean for it to be past or present.  
4) She said that they would have stayed at home, but if it had raining, we wouldn't have met in the park. But for this meeting, I wouldn't have known, what happened to our friend. <em>-Sorry but I don't understand the meaning behind this in order to correct it.  </em>
5) I haven't didn't have the study book. The teacher said that if I had had have it, I would have been able to doing all exercises by now.