After? until?

[Progress]

Cross the river and walk straight on ( ) you cross the rail way tracks.

After can come in the ( ),if you have to walk on for more distance beyond the rail way tracks?
If you use until there, what does the sentence mean?

Thank you very much

[Casiopea]

Originally Posted by Progress

Cross the river and walk straight on ( ) you cross the rail way tracks.

After can come in the ( ),if you have to walk on for more distance beyond the rail way tracks?
If you use until there, what does the sentence mean?

Thank you very much

after means, walk in a straight line once you've crossed the railway tracks.

until means, walk in a straight line once you've crossed the river, and then stop walking in a straight line once you've crossed the railway tracks.

[Progress]

Thank you very much, Casiopea. I understand.

[Casiopea]

You're welcome.
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