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?]

2 answers

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