1. If you __________ (to drive) along the river bank it _______ (to be) twenty miles out of your way.
2. If you _____ (to take) your mobile phone into class, it __________ (must) be turned off.
3. If you __________ (to close) the door, it _________ (to lock) automatically.
4. When I ___________ (to cook) salads, I _________ (to use) only olive oil.