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general::
Phrase(s): One thing leads to another.
One event sets things up for another event, and so on. (As an explanation of how little things lead to big problems.) • I kept spending more and more money until I was broke. You know how one thing leads to another. • He bought a car, then a house, then a boat. One thing leads to another.
McGrawhill's American Idioms And Phrasal Verbs