diff --git a/book/en/src/preface.md b/book/en/src/preface.md
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@@ -8,7 +8,7 @@
 # Preface
 
 This book contains user level documentation for the Real-Time Interrupt-driven Concurrency
-(RTIC) framework. The API reference available [here](../../api/).
+(RTIC) framework. The API reference is available [here](../../api/).
 
 Formerly known as Real-Time For the Masses.