PART TWO (see other comment for part one)

Now where it gets a little more confusing is where "just as" can replace "as soon as" completely. This has a little more nuance. "Just as" usually implies an order of events where there is a little bit of overlap between the first and second event.

Just means equal. If something happens "just as" something else happens, then they happened at the same time. Whereas "as soon as" means one thing fully ends before the other begins.

"I will go to sleep just as I finish this movie" = This doesn't really work. It looks like you will fall asleep as the movie is still ending (because "just as" implies some level of overlap).

You would have to say,

"I will go to sleep just as soon as I finish this movie", in order to show what the order of tasks are (first the movie ends, and THEN you sleep).

"I will never play chess with him again because he's a cheater! Just as I looked away, he moved the pieces." = This works, but changes the meaning slightly! Now we feel like we caught him moving the pieces, because he did so at the same time as the narrator looking away.

Just means equal. If something happens "just as", then it happens <em>at the same time</em> as something else. Whereas "as soon as" means one thing <em>fully ends </em>before the other begins.

I hope this helps!

PART ONE (see my other comment for part 2)

They can be used interchangeably in some scenarios, but not others. They can also be combined.

"As soon as" is talking about the order of tasks. Usually you are saying you will do one thing directly after another, or that something happened directly after something else.

"I will go to sleep as soon as I finish this movie" = First the movie ends, then I will go to sleep

"I will never play chess with him again because he's a cheater! As soon as I looked away, he moved the pieces." = First I looked away, then he moved the pieces

"Just as" can be a comparison between two things, implying they are <em>equals. </em>

"Oranges are just as tasty as apples!" = oranges and apples are equally tasty

"You say he is mean, but you are just as rude as him." = the two people are equally rude

In these instances, you could only use "just as". They would not make sense with "as soon as" since you are not talking about time or the order of tasks.

That being said, "just" can be added to "as soon as", to make "just as soon as". Although it is not a perfect translation, just means equal, and it helps to think of "just" like you would think of "exactly".

"Oranges are exactly as tasty as apples!" = the meaning hasn't changed. The sentence is still comparing the fruits, and judging them to be equal.

Or, "I will go to sleep exactly when this movie ends." = the meaning hasn't changed. The sentence is still about the order of tasks.

"Just as soon as" is only emphasizing that you will do second task RIGHT AWAY after the first task.

I didn't have room to finish: This is PART ONE of my answer

It just depends on what you want to say.

‘Just as’ I stepped around the corner, I was greeted by my children with hugs and kisses.

‘As soon as’ I finish the laundry, I’ll go and wash the dishes.

Kimberly Jean,

Thank you so much, you helped me a lot!