https://www.englishclub.com/esl-forums/viewtopic.php?t=34661
1. I saw him on the bus.
2. I saw him in the bus.
3. Mary was working at the Slade, where she went daily on a bus.
4. Mary was working at the Slade, where she went daily in a bus.
Which of the above sentences is not acceptable?
What's the difference between "on the/a bus" and "in the/a bus"?