- In entering the room, she saw him.
- On entering the room, she saw him.
- As she entered the room, she saw him.
- When she entered the room, she saw him.
What are the differences between these sentences? They all refer to something that happens at the same time as something else, but does one make the second action (she saw him) evoke more quickness than another? does one of the examples make the two actions sound more consequential rather than simultaneous?
Regarding in TheFreeDictionary says:
3.b. During the act or process of:
tripped in racing for the bus.
(So, that means that it was on entering the room that she saw him, not when she was doing something else.)
but Collins says:
You use on when mentioning an event that was followed by another one.
She waited in her hotel to welcome her children on their arrival from London. On reaching Dubai, the evacuees are taken straight to Dubai international airport.