Use the Gerund instead of the subordinate clauses.
1. The witness reported that he had seen a dark saloon car parked outside the bank.
2. She dislikes when the children prompt one another and she always gets very angry.
3. He wrote he would stay in Paris another week and didn’t explain why he was obliged to do so.
4. Nell denies that he is a bore.
5. We decided that we should join them in Glasgow.