diff --git a/book/en/src/by-example/message_passing.md b/book/en/src/by-example/message_passing.md
index 0dc8f85814..5665c36ce5 100644
--- a/book/en/src/by-example/message_passing.md
+++ b/book/en/src/by-example/message_passing.md
@@ -3,7 +3,7 @@
 Software tasks support message passing, this means that software tasks can be spawned
 with an argument: `foo::spawn(1)` which will run the task `foo` with the argument `1`.
 
-Capacity sets the size of the spawn queue for the task, if not specified capacity defaults to 1.
+Capacity sets the size of the spawn queue for the task. If it is not specified, the capacity defaults to 1.
 
 In the example below, the capacity of task `foo` is `3`, allowing three simultaneous
 pending spawns of `foo`. Exceeding this capacity is an `Error`.