Upon vs. on

[Allen165]

"It will be repealed upon/on the expiry of the implementation deadline."

Is there any difference between "upon" and "on" here? My view is that "upon" is simply more formal.

Thanks!

 

[Coolfootluke]

I am not a teacher.

"Upon" is decidedly formal there, but I think it is also better. "On" has so many meanings that it's nice when we can help the reader with "upon" once in a while, and I think that when we mean the brink of an event we should, if we can get away with it. Upon opening her present, she began to laugh. Upon reaching the top of the ladder, Randy made the mistake of looking down.

 

[Allen165]

I am not a teacher.

"Upon" is decidedly formal there, but I think it is also better. "On" has so many meanings that it's nice when we can help the reader with "upon" once in a while, and I think that when we mean the brink of an event we should, if we can get away with it. Upon opening her present, she began to laugh. Upon reaching the top of the ladder, Randy made the mistake of looking down.

That sentence is from a textbook. The authors wrote "on," and I didn't actually think one could use "on" like that; I thought "upon" was a must in such a construction.

"On arriving in his hometown, he went to a bar."

The above sentence means that right after he arrived he went to a bar. Correct?

Thanks!

 

[Coolfootluke]

Correct. Strictly speaking, there are very few exceptions to the rule that you can use "on" wherever you can use "upon" (but not vice-versa); once upon a time, feeling put upon and the like cannot take "on".