2. They speak Friench to her, not English, so her English doesn't improve.

If they didn't Friench to her, not English, her English would improve.
3. He doesn't work overtime , so he doesn't earn as much as I do

- If he worked overtime, he would earn as much as I do
4. You didn’t tell me we had run out of bread, so I didn’t buy any.
⇨ If you had told me we had run out of bread I’d have bouhgt some
5. ⇒ If I had seen the signal , I would have stopped