They missed the bus, so they arrived late

1. They missed the bus, so they arrived late.
=> if
2. She is too tired, so she can’t finish the work.
=> if
3. He didn’t study, so he failed the test.
=> if
4. It rained heavily, so the match was canceled.
=> if
5. The car broke down, so they had to call a mechanic.
=> if
6. They don’t have a reservation, so they can’t get a table.
=> if
7. The movie was sold out, so they couldn’t watch it.
=> if
8. She lost her keys, so she couldn’t enter the house.
=> ff
9. He is allergic to seafood, so he can’t eat shrimp.
=> if
10. They didn’t bring their umbrellas, so they got wet in the rain.
=> if