Fix typo

Author: Yiyun333

content/en/docs/refguide/modeling/application-logic/workflows/boundary-events.md

@@ -82,7 +82,7 @@ With non-interrupting boundary events, the parent activity remains active/in pro
 
 ## Boundary Event Variables
 
-Boundary events have dedicated variables that can be used to get direct access to the values of the parent activity if it is either a user ask or Call workflow activity. You can get information such as the parent activity's `DueDate`, which can be used in the boundary event flow and its expressions. For instance, you can use the expression `addDays($ParentTask/DueDate, -2)` to configure a timer boundary event so that it is triggered two days before the due date of its parent user task.
+Boundary events have dedicated variables that can be used to get direct access to the values of the parent activity if it is either a user task or Call workflow activity. You can get information such as the parent activity's `DueDate`, which can be used in the boundary event flow and its expressions. For instance, you can use the expression `addDays($ParentTask/DueDate, -2)` to configure a timer boundary event so that it is triggered two days before the due date of its parent user task.
 
 The list of variables is described below: