1. The furniture was too old for us to keep.
=> It was such old furniture that we wouldn't / couldn't keep it.
2. Nobody has cleaned the streets this week.
=> The streets haven't been cleaned this week.
3. While mending the road, they accidentally blocked our water pipes.
=> They accidentally cut off our water supplying while mending the road.
4. He brought the umbrella along but it didn't rain.
=> He needn't have brought the umbrella along.
5. While I strongly disapprove of your behavior,  I will help you this time.
=> Despite my strong disapproval of your behavior, I will help you this time.
=))