diff --git a/pills/04-basics-of-language.xml b/pills/04-basics-of-language.xml
index 5ea34c4..f799e7a 100644
--- a/pills/04-basics-of-language.xml
+++ b/pills/04-basics-of-language.xml
@@ -338,7 +338,7 @@
     <title>Laziness</title>
 
     <para>
-      Nix evaluates expression only when needed. This is a great feature when
+      Nix evaluates expressions only when needed. This is a great feature when
       working with packages.
     </para>