diff --git a/08-Considering_Performance.md b/08-Considering_Performance.md
index 7c651f6..313f000 100644
--- a/08-Considering_Performance.md
+++ b/08-Considering_Performance.md
@@ -59,7 +59,7 @@ After you build using Templight, you will need to analyze the results. The [temp
 
 #### Don't Unnecessarily Include Headers
 
-The compiler has to do something with each include directive it sees. Even if it stops as soon as it seems the `#ifndef` include guard, it still had to open the file and begin processing it.
+The compiler has to do something with each include directive it sees. Even if it stops as soon as it sees the `#ifndef` include guard, it still had to open the file and begin processing it.
 
 [include-what-you-use](https://github.com/include-what-you-use/include-what-you-use) is a tool that can help you identify which headers you need.