diff --git a/2-ui/99-ui-misc/01-mutation-observer/article.md b/2-ui/99-ui-misc/01-mutation-observer/article.md
index a1602f33..1e9be8fb 100644
--- a/2-ui/99-ui-misc/01-mutation-observer/article.md
+++ b/2-ui/99-ui-misc/01-mutation-observer/article.md
@@ -1,7 +1,7 @@
 
 # Mutation observer
 
-`MutationObserver` is a built-in object that observes a DOM element and fires a callback if there are changes.
+`MutationObserver` is a built-in object that observes a DOM element and fires a callback when it detects a change.
 
 We'll first take a look at the syntax, and then explore a real-world use case, to see where such thing may be useful.