diff --git a/README.md b/README.md
index 8ced8d7..ecbb1b2 100644
--- a/README.md
+++ b/README.md
@@ -26,6 +26,7 @@ Language structures used include:
 * Iteration
 * Actions (as in `file.forEachLine`)
 * Pattern matching (simple example using `when` expression)
+* String interpolation
 
 Kotlin library features used include:
 
diff --git a/src/three_feature.kt b/src/three_feature.kt
index c7d3022..c56850f 100644
--- a/src/three_feature.kt
+++ b/src/three_feature.kt
@@ -45,6 +45,7 @@ fun main(args: Array<String>) {
         }
 
         // input and output from console are as easy as `println()` and `readline()`
+        // uses string interpolation for easier formatting
         println("$course:\n\t$letter ($average)\n")
     }
 }
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