Fix typo in README description

Author: lauracmurphy

README.md

@@ -4,6 +4,6 @@
 [![License: CC BY 4.0](https://img.shields.io/badge/License-CC_BY_4.0-blue.svg)](https://creativecommons.org/licenses/by/4.0/)
 [![Twitter](https://img.shields.io/twitter/follow/petebankhead?style=flat)](https://twitter.com/petebankhead)
 
-This book tries explain the main ideas of bioimage analysis in a practical and engaging way.
+This book tries to explain the main ideas of bioimage analysis in a practical and engaging way.
 
 You're currently looking at the ReadMe - for the actual book, see https://bioimagebook.github.io