Learn English – What’s the meaning of “upon doing something”


I come across the following sentence.

Upon compiling his results for many thousands of plants, Mendel
concluded that the characteristics could be divided into what he
called dominant and recessive traits.

And I was told: After the first part (compile his result) was done, then he made a conclusion. Since it is using compiling which looks like part 1 and part 2 happened that same time. How do you thing?

Best Answer

Upon doing something, someone realizes something.

On doing something,someone realizes something.

Those both mean: When that someone did that thing.

Upon reading this question, I was surprised. On reading this question, I was surprised.

When I read this question, I was surprised.

Upon verb+ing is formal.