Question

1. He is swimming in the river.
2. He is swimming on the river.
[Can we use on as in #2?]

3. He is on top of the bus.
4. He is on the top of the bus.
[Can we use both expressions?]

5. He is on the bus.
6. He is on top of the bus.
7. He is in the bus.
[Does #5 mean both #6 and #7?]

Answer 1

1 - OK
2 - No
3 and 4 - Yes
5 and 7 mean the same thing, but 6 is quite different!

Answer 2

I like free fire