1. I don’t play tennis as well as you do.
⇒You play tennis better than I do.
2. I haven’t been to the dentist’s for two years.
⇒It’s two years since I last went to the dentist’s.
3. Whenever she went to Paris she bought a new dress.
⇒She never went to Paris without buying a new dress.
4. I spent seven years at secondary school and then I went to university.
⇒After having spent seven years at secondary school I went to university.
5. It’s not worth living to make her change her mind.
⇒There’s no need to make her change her mind.