Fix grammar (#3781)

entity-framework/core/modeling/shadow-properties.md

@@ -7,7 +7,7 @@ uid: core/modeling/shadow-properties
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 # Shadow and Indexer Properties
 
-Shadow properties are properties that aren't defined in your .NET entity class but are defined for that entity type in the EF Core model. The value and state of these properties is maintained purely in the Change Tracker. Shadow properties are useful when there's data in the database that shouldn't be exposed on the mapped entity types.
+Shadow properties are properties that aren't defined in your .NET entity class but are defined for that entity type in the EF Core model. The value and state of these properties are maintained purely in the Change Tracker. Shadow properties are useful when there's data in the database that shouldn't be exposed on the mapped entity types.
 
 Indexer properties are entity type properties, which are backed by an [indexer](/dotnet/csharp/programming-guide/indexers/) in .NET entity class. They can be accessed using the indexer on the .NET class instances. It also allows you to add additional properties to the entity type without changing the CLR class.