Rewrite each sentence, beginning as shown: If you do the shopping, I'll cook lunch

Rewrite each sentence, beginning as shown
1.If you do the shopping, I'll cook lunch       
  You................................................​
2. I might be late.If so, start without me
   If I.................................................
3.The fire was brought under control thanks to the night watch-man
   If it hadn't.........................................
4.If you want my advice, I'd think twice about buying a car like that
   If I...............................................
5. If the painting is finished by Saturday, we 'll pay you extra
   Finish....................................