Part A
1. If it rain, we will stay at home.
2. If you don't know the way, I will pick you up.
3. My mum will bake a cake if you come to see us.
4. They will come to his party if he invite them.
5. I will visit my grandparents if I have a long holiday.
Part B
1. If you studied harder, you might get better marks in your tests.
2. If I become rich, I would travel around the world.
3. She should come to the market with us if she haven't to work.
4. We would send you a message if we got to the city.
5. I would call you back if I arrived at home.