Update README.md

Matt A · Matt A · commit 92b604b938c9 · 2016-03-07T17:41:19.000-05:00
diff --git a/README.md b/README.md
@@ -1,5 +1,5 @@
 # GitBook Default Theme
 
-This is the default theme for GitBook since version `3.0.0`. It can be used as a template for theming books or cam be extend.
+This is the default theme for GitBook since version `3.0.0`. It can be used as a template for theming books or can be extended.
 
 ![Image](https://raw.github.com/GitbookIO/theme-default/master/preview.png)
