Insert missing word.

content/courses/ada-idioms/chapters/introduction.rst

@@ -16,7 +16,7 @@ how can one best use the Ada language to express an elegant solution?".
 
 Design patterns [1]_ are intended to answer that question, and indeed
 some would equate idioms with design patterns. But what we have in mind
-is more general does not focus on design patterns.
+is more general and does not focus on design patterns.
 
 For example, :wikipedia:`Reference Counting <Reference_counting>` is a
 well-known approach to tracking and managing the storage for objects and